Method, device, computer program and computer-readable storage medium for charging energy store

Abstract

In a method for charging an energy store, battery information is received. The battery information represents a state of the battery. The state of charge, the cell temperature and the cell resistance of the energy accumulator are determined. A charging factor is determined as a function of the battery information, the state of charge of the energy accumulator, the cell temperature and the cell resistance. A charging power is determined as a function of the charging factor and the energy store is charged with the determined charging power.

Description

Technical Field

[0001] The invention relates to a method for charging an energy accumulator. The invention further relates to a device for charging an energy accumulator. The invention further relates to a computer program for charging an energy accumulator. The invention further relates to a computer-readable storage medium on which the computer program is stored. Background Art

[0002] Silicon-containing active materials are frequently used in current electrical energy storage devices in order to increase the energy density of the electrical energy storage devices. Aging effects occur due to frequent charging and discharging, in particular rapid charging, of the electrical energy storage devices. Summary of the invention

[0003] The invention is based on the object of facilitating the gentle charging of an energy storage device.

[0004] This object is achieved by the features of the independent claims. Advantageous embodiments are characterized in the dependent claims.

[0005] The invention is characterized by a method for charging an energy storage device and a corresponding device.

[0006] In the method, battery information is received, wherein the battery information represents a state of the battery. In addition, the method determines a state of charge, a cell temperature, and a cell resistance of the energy accumulator. A charging factor is determined based on the battery information, the state of charge, the cell temperature, and the cell resistance of the energy accumulator. A charging power is determined based on the charging factor, and the energy accumulator is charged with the determined charging power.

[0007] The energy storage device is in particular an electrical energy storage device of an electric vehicle or a hybrid vehicle, for example a lithium-ion battery, which comprises a negative electrode, the so-called “anode”, and a positive electrode, the so-called “node”.

[0008] The anode has, for example, an anode active material, which includes, for example, a material from the group consisting of carbonaceous materials, silicon, silicon suboxides, silicon alloys, titanium, titanium oxides, and mixtures thereof. In particular, the anode active material is selected from the group consisting of synthetic graphite, natural graphite, graphene, racemic carbon, doped carbon, hard carbon, soft carbon, carbon 60, silicon-carbon composites, silicon, surface-coated silicon, silicon suboxides, silicon alloys, titanium, titanium oxides, lithium, and mixtures thereof.

[0009] In particular, the anode material is an anode material having a silicon content.

[0010] The cathode has, for example, a cathode active material. The cathode active material may have a plurality of particles that are bound to an electrode binder. The cathode active material may have a layered oxide, such as lithium nickel cobalt manganese oxide (NMC), lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LCO) or lithium nickel cobalt oxide (LNCO). The layered oxide may be an overlithiated layered oxide (OLO, overlithiated layered oxide). Other suitable cathode active materials are compounds with a spinel structure, such as lithium manganese oxide (LMO) or lithium manganese nickel oxide (LMNO) or compounds with an olivine structure, such as lithium iron phosphate (LFP, LiFePO4) or lithium manganese iron phosphate (LMFP).

[0011] Until now, the rapid charging capability of lithium-ion cells has been limited by undesirable side reactions, in particular lithium plating on graphite anodes. In order to counteract lithium plating on graphite anodes during rapid charging, for example, a step-by-step characteristic curve with a decreasing current as the state of charge increases can be used. However, the silicon content on the anode side changes the rapid charging characteristics of the energy storage device.

[0012] The described method makes it possible to adapt the charging characteristic curve as a function of battery information, state of charge, cell temperature and cell resistance of the energy store, thereby enabling the energy store to be charged in a sensitive manner.

[0013] According to an alternative specific embodiment, the battery information includes information about the material composition of the electrodes of the energy storage device and / or about the silicon content of the electrodes of the energy storage device.

[0014] The charging characteristic curve for the rapid and gentle charging of an electrical energy storage device may differ significantly depending on the material composition of the electrode and / or the silicon content of the electrode. Especially in the case of anode materials with a silicon content, a reduction in the initial charging power can help to reduce the aging effects of the electrical energy storage device.

[0015] The described method makes it possible to adapt the charging characteristic curve as a function of battery information, in particular information about the material composition and / or the silicon content, so that the energy store can be charged in a gentle manner.

[0016] According to an alternative embodiment, the battery information includes information about a voltage characteristic curve for an electrode material and / or a voltage range for a phase transition.

[0017] The charging characteristic curve for the rapid and gentle charging of an electrical energy storage device can vary significantly depending on the voltage characteristic curve of the electrode material and / or the voltage range of the phase transition. Precisely at the phase transition of the silicon-containing anode material, a reduction in the charging power can help to reduce the aging effects of the electrical energy storage device.

[0018] The described method enables such an adaptation of the charging characteristic curve as a function of battery information, in particular information about the voltage characteristic curve of the electrode material and / or the voltage range of the phase transition of the electrode material, so that the energy store can be charged in a gentle manner.

[0019] According to an alternative specific embodiment, the charging power is determined as a function of one or more charging parameters, including a planned charging duration and / or an amount of energy to be charged.

[0020] By determining the charging power as a function of one or more charging parameters, the charging power required for charging from the first state of charge to the second state of charge and the charging time required are determined.

[0021] The reference charging power determined as a function of one or more charging parameters serves as a reference for further adaptation of the charging power via the charging factor.

[0022] According to an optional specific embodiment, the energy storage device is charged in such a way that the charging power is adapted in a first state of charge range up to a first state of charge by a first charging factor and in a second state of charge range between the first state of charge and the second state of charge by a second charging factor, wherein the charging power is different in the first range and the second range.

[0023] Depending on the battery information, the state of charge of the energy storage device, the cell temperature and the cell resistance, it may be useful to divide the charging power into a plurality of state of charge ranges according to the charging factor, wherein a charging factor is determined for each state of charge range in order to charge the energy storage device in a sensitive manner.

[0024] For example, the energy storage device includes two state of charge regions based on battery information, the state of charge of the energy storage device at 20% of the current state of charge, the cell temperature, and the cell resistance. The first state of charge region is between 20% of the current state of charge and 30% of the current state of charge, and the second state of charge region is between 30% and 100%.

[0025] In order to protect the silicon-containing anode, the energy store is charged in a first state-of-charge range, for example, at a charge rate of 1 C, and in a second state-of-charge range, for example, at a charge rate of 3 C.

[0026] According to an alternative embodiment, battery information, state of charge, cell temperature and cell resistance are weighted when determining the charge factor.

[0027] The weighting can ensure that safety-critical parameters, such as the cell temperature, have a more significant influence on the charging factor and thus the charging power is more strongly adapted.

[0028] According to an alternative specific embodiment, the charging factor is also determined as a function of the cell voltage of the energy storage device.

[0029] By also determining the charging factor as a function of the cell voltage of the energy accumulator, it can be ensured that the cell voltage limits the charging power used to charge the energy accumulator.

[0030] The invention is also characterized by a computer program for charging an energy storage device, the computer program comprising instructions which, when executed by a computer, cause the computer to perform the method for charging an energy storage device.

[0031] The present invention is also characterized by a computer-readable storage medium on which the computer program is stored.

[0032] The computer-readable storage medium comprises, in particular, a medium readable by a data processing device, on which the program code is stored. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] An embodiment of the present invention is described in more detail below with the aid of a schematic diagram. In the figure:

[0034] Figure 1 A flow chart showing a procedure for charging an energy storage device,

[0035] Figure 2 A diagram showing a charging characteristic curve in stages,

[0036] Figure 3 shows a charging characteristic curve with an initial linear increase in charging power,

[0037] Figure 4 A charging characteristic curve is shown with an initial stepwise increase in charging power. DETAILED DESCRIPTION

[0038] Figure 1 A flow chart of a program for charging an energy storage device is shown.

[0039] The device 50 is designed to process programs. For this purpose, the device 50 has, in particular, a computing unit, a program and data memory and, for example, one or more communication interfaces. The program and data memory and / or the computing unit and / or the communication interface can be formed in one structural unit and / or distributed on a plurality of structural units.

[0040] The device 50 may also be referred to as a device for charging an energy store.

[0041] For this purpose, in particular a program is stored in the program and data memory of device 50 .

[0042] The program begins in step S101 , wherein variables can be initialized if necessary.

[0043] In step S103, battery information is received, wherein the battery information represents the status of the battery.

[0044] For example, battery information is stored in a battery management system.

[0045] The battery information includes, for example, information about the material composition of the electrodes of the battery and / or about the silicon content of the electrodes of the energy storage device and / or information about the voltage characteristic curve of the electrode material and / or about the voltage range of the phase transition of the electrode material.

[0046] The information about the material composition of the electrode and / or about the silicon content of the electrode of the battery includes, for example, information about the electrode material used for the anode, for example a material containing silicon oxide having a silicon content of 20% of the active material of the anode.

[0047] The information about the voltage characteristic curve of the electrode material and / or the voltage range for the phase change of the electrode material includes, for example, information about the voltage range of the anode material and / or the voltage range for the phase change of the anode material during the charging process, such as a voltage range of the cathode voltage and the overall cell voltage from 3.0V to 4.2V and a voltage range of the anode voltage from 0.05V to 1.5V.

[0048] In step S105 , the state of charge, the cell temperature and the cell resistance of the energy storage device are determined.

[0049] For example, the cell temperature is determined at the cell housing by a temperature sensor. For example, the state of charge of the energy storage device is determined by the static voltage of the energy storage device. For example, the energy storage device has a device for determining the cell resistance.

[0050] In step S107 , the charging factor is determined based on the battery information, the state of charge of the energy storage device, the cell temperature and the cell resistance.

[0051] For example, a lookup table for battery information, state of charge of the energy storage device, cell temperature and cell resistance and / or a calculation basis for the charging factor based on the battery information, state of charge of the energy storage device, cell temperature and cell resistance is stored in the device 50 , from which the charging factor is determined.

[0052] For example, the charge factor is reduced as soon as the temperature exceeds a temperature threshold value, here for example 40° C. If the temperature increases beyond the temperature threshold value, the charge factor is reduced permanently, for example.

[0053] For example, when the battery information includes information about the silicon content present in the anode active material and the state of charge is below a state of charge threshold, here for example 30%, the charge factor is reduced according to the battery information and the state of charge. For example, once the state of charge reaches above the state of charge threshold, the charge factor is increased.

[0054] For example, once the cell resistance exceeds a cell resistance threshold, the charging factor is reduced. When the cell resistance increases beyond the cell resistance threshold, the charging factor is reduced continuously, for example.

[0055] When determining the charge factor, weights are assigned to the battery information, the state of charge, the cell temperature and the cell resistance. For example, the cell temperature is assigned a higher weight than the cell resistance. For example, the parameter of the cell temperature is substituted twice into the determination of the charge factor and the parameters of the battery information, the state of charge and the cell resistance are substituted once respectively.

[0056] The charging factor is also determined as a function of the cell voltage of the energy storage device.

[0057] In step S109, the charging power is determined according to the charging factor. Here, the charging power is determined according to one or more charging parameters. The charging parameters include the planned charging duration and / or the amount of energy to be charged.

[0058] For example, the accumulator should be charged from a state of charge of 20% to a state of charge of 80% within a charging duration of 20 minutes.

[0059] The charging power is determined as a function of the charging factor such that the charging power is adapted in a first state of charge range up to a first state of charge by a first charging factor and in a second state of charge range between the first state of charge and a second state of charge by a second charging factor, wherein the charging power is different in the first range and in the second range.

[0060] In step S111 , the energy storage device is charged with the determined charging power.

[0061] The energy storage device is, for example, an energy storage device comprising an anode having silicon oxide and silicon, in particular a silicon content of about 20%. Alternatively, the anode can, for example, have graphite and silicon oxide as active materials, in particular a silicon oxide content of about 20%.

[0062] In a first example, the charging of the energy storage device can be carried out according to Figure 2 The example in FIG. 1 is based on a diagram with a staged charging characteristic curve.

[0063] For example, the energy store is charged from an original state of charge Z11, here for example 20%, to a final state of charge Z15, here for example 80%. Based on the battery information about the silicon content of the silicon oxide anode and the state of charge of 20%, for example, a charging factor is determined, by which the energy store is charged with a charging power L11, here for example 0.8 C, because silicon, due to its inherent material properties, is subject to strong aging effects in the low state of charge range at high charging currents.

[0064] At the state of charge Z12 , here for example 30%, a charging factor is determined, by which the energy store is charged with a charging power L14 , here for example 2 C, to a state of charge Z13 , here for example 60%.

[0065] For example, at a state of charge of 60%, the charging factor is then redefined in such a way that the charging power is reduced to a charging power L13 , here, for example, 1.5 C, between states of charge Z13 and Z14 , here, for example, 70%.

[0066] For example, at a state of charge of 70%, the charging factor is then redefined such that the charging power is reduced to a charging power L12 , here, for example, 1 C, between states of charge Z14 and Z15 , ie, between 70% and 80%.

[0067] In a second example, the charging of the energy storage device can be carried out according to Figure 3 The example in is based on a diagram including a charging characteristic curve with an initial linear increase in charging power.

[0068] For example, the charging factor is continuously determined, whereby the charging power is continuously increased according to the charging factor from a first state of charge Z21, here for example 20%, to a second state of charge Z22, here for example 30%, and the energy storage device is charged from state of charge Z22 at a constant charging power L21, here for example 1.5 C, to a state of charge Z23, here for example 80%.

[0069] The program ends in step S113 and can be restarted if necessary.

[0070] In a third example, the charging of the energy accumulator can be performed as follows Figure 4 The example in is based on a diagram including a charging characteristic curve with an initial stepwise increase in charging power.

[0071] For example, the energy store is charged from an original state of charge Z31, here for example 20%, to a final state of charge Z34, here for example 80%. Based on the battery information about the silicon content of the silicon oxide anode and the state of charge of 20%, for example, a charging factor is determined, by which the energy store is charged with a charging power L31, here for example 0.8 C, because silicon, due to its inherent material properties, is subject to strong aging effects in the low state of charge range at high charging currents.

[0072] At the state of charge Z32 , here for example 30%, a charging factor is determined, by which the energy store is charged with a charging power L32 , here for example 1 C, to a state of charge Z33 , here for example 40%.

[0073] For example, in state of charge Z33 the charging factor is then redefined in such a way that the charging power is increased between states of charge Z33 and Z34 to charging power L33 , here for example 2C. Reference numerals list

[0074] Steps S1-S9

[0075] 50 devices

[0076] Z11-Z15; Z21-Z23; Z31-Z34 charge state

[0077] L11-L14; L21; L31-L33 charging power

Claims

1. A method for charging an energy storage device, the method comprising: - receiving battery information, wherein the battery information represents a status of a battery, - determine the state of charge of the accumulator, the cell temperature and the cell resistance, - Determine the charge factor based on the battery information, the charge state of the accumulator, the cell temperature and the cell resistance, - determining a charging power according to said charging factor, - Charging the energy storage device with the determined charging power.

2. The method according to claim 1, wherein: The battery information includes information about the material composition of the electrodes of the energy storage device and / or about the silicon content of the electrodes of the energy storage device.

3. The method according to any one of the preceding claims, wherein: The battery information includes information about the voltage characteristic curve for the electrode material and / or about the voltage range for the phase transition of the electrode material.

4. The method according to any one of the preceding claims, wherein: The charging power is determined as a function of one or more charging parameters, including a planned charging duration and / or an amount of energy to be charged.

5. The method according to any one of the preceding claims, wherein: The energy store is charged such that the charging power is adapted in a first state of charge range up to a first state of charge by a first charging factor and in a second state of charge range between the first state of charge and a second state of charge by a second charging factor, wherein the charging power is different in the first range and the second range.

6. The method according to any one of the preceding claims, wherein: When determining the charge factor, weights are assigned to the battery information, state of charge, cell temperature and cell resistance.

7. The method according to any one of the preceding claims, wherein: The charging factor is also determined as a function of the cell voltage of the energy storage device.

8. A device for charging an energy storage device, wherein: The device is designed to carry out a method according to one of claims 1 to 7 . 9 . A computer program for charging an energy storage device, the computer program comprising instructions which, when the computer program is executed by a computer, cause the computer to carry out the method according to claim 1 . 10 . A computer-readable storage medium on which the computer program according to claim 9 is stored.

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