DE102018122678A1 - Charger for a vehicle - Google Patents

Abstract

A charging device (30) for charging an energy store (50), in particular for a vehicle (20), has a control device (32) and a heating device (54), which control device (32) has a receiving unit (35) and a temperature controller (34) which control unit (35) is designed to receive a temperature value (T) characterizing the temperature at the energy store (50) and a state of charge value (SOC) characterizing the state of charge of the energy store (50), which control device (32) is designed to during a charging process to determine the temperature setpoint (T_S) as a function of the state of charge value (SOC), and which temperature controller (34) is designed to use the heating device (54) to bring the temperature value (T) to the temperature setpoint (T_S) regulate.

Description

The invention relates to a charging device for a vehicle.

The JP 2010 259308 A shows a charging process in which the charging control carries out a charge with a maximum charge amount, wherein electrical charging energy is supplied to auxiliary devices such as an air conditioning system or a heat store.

The CN 107 317 067 A shows a thermal control device for a battery, in which, when the battery temperature is below a predetermined limit value, an increase in the battery temperature takes place by the battery being charged and discharged alternately.

The US 2010 085019 A shows a battery temperature control system that determines a maximum charge current and a maximum discharge current as a function of the current, the voltage and the temperature of a high-voltage battery and then carries out a limitation of the charge current to the maximum charge current and a limitation of the discharge current to the maximum discharge current.

The WO 2017/099649 A1 shows a hybrid vehicle with an internal combustion engine, a hybrid battery and an accessory battery. If the charging time is not fixed in a first state, a maximum charging current is supplied to the accessory battery if its state of charge is below a limit value in order to be able to operate the starter. In contrast, if the state of charge is above the limit value, the hybrid battery is supplied with a maximum charging current. On the other hand, if the charging time is set in a second state, the state of charge of the hybrid battery and the accessory battery is determined, and if possible, the charging takes place with a non-maximum charging current such that the batteries are full at the end of the charging time.

The GB 254280 B shows a battery management system with a controller and a temperature sensor which determines the temperature of the battery. The controller controls the charging current depending on the temperature determined, and the cells are balanced if the charging current exceeds a predetermined upper limit.

It is therefore an object of the invention to provide a new loading device.

The object is achieved by the subject matter of claim 1.

A charging device for charging an energy store has a control device and a heating device, the control device has a receiving unit and a temperature controller, the receiving unit is designed to receive a temperature value characterizing the temperature at the energy store and a charge state value characterizing the state of charge of the energy store, which control device is designed to do so is to determine the temperature setpoint as a function of the state of charge value during a charging process, and which temperature controller is designed to regulate the temperature value to the temperature setpoint via the heating device.
With such a charging device, the overall efficiency of the charging process of the vehicle can be increased and energy can be saved when considering the entire charging process.

According to a preferred embodiment, the control device is designed to continuously determine the temperature setpoint as a function of the state of charge value during the charging process at predetermined time intervals. The temperature setpoint is therefore also adjusted during the charging process.

According to a preferred embodiment, the control device is designed to increase the temperature setpoint at a predetermined temperature of the energy store only when the state of charge value has reached a predetermined value. Charging takes place without activating the heating device until the charge state value has reached the specified value at the specified temperature.

According to a preferred embodiment, the control device is designed to determine the temperature setpoint as a function of the state of charge value during a charging process such that the temperature setpoint is not constant in the range of the state of charge between 0% and 100%. This enables the temperature setpoint to be adapted to the temperature actually required for the given parameters.

According to a preferred embodiment, the control device is designed to determine the temperature setpoint as a function of the state of charge value during a charging process such that at least three different temperature setpoints, preferably at least six different temperatures, occur for the range of the state of charge between 0% and 100% Setpoints. This number leads to an exact mapping of the required temperature.

According to a preferred embodiment, the control device is designed to maintain the temperature corresponding to the temperature setpoint increasing the state of charge at least in some areas. The increase enables effective charging even when the charge level increases.

According to a preferred embodiment, the control device is designed to only activate the heating device for heating during a charging process when the temperature corresponding to the temperature value is lower than the temperature corresponding to the temperature setpoint value for the first time. This measure prevents the heating device from being activated prematurely.

According to a preferred embodiment, the control device is designed to determine the temperature setpoint as a function of the state of charge value during a charging process such that a charging process is possible at the temperature of the energy store corresponding to the temperature setpoint and the state of charge of the energy store corresponding to the state of charge value but at least partially at the temperature corresponding to the temperature setpoint, a state of charge of 100% cannot be achieved. This prevents excessive temperature increases at an early stage.

According to a preferred embodiment, the control device is designed to determine the temperature setpoint as a function of the state of charge value during a charging process in such a way that a maximum increase in the state of charge of the energy store at the temperature of the energy store corresponding to the temperature setpoint and the state of charge corresponding to the state of charge Energy storage is possible, which is below 40% of the maximum charge. If, for example, the state of charge is 30%, the temperature setpoint must be increased to 69% at the latest in order to be able to continue with the charging process. Such an increase may naturally be necessary earlier.

According to a preferred embodiment, the control device has at least two functions for determining the desired temperature value as a function of the charge state value, and the control device is designed to enable selection of one of the at least two functions for the charging process. The charging process can be influenced by this measure. If rapid charging is desired and high charging capacities are possible, a first curve can be selected that has a poorer efficiency. With a normal charge, however, a second curve can be selected. Naturally, further curves or profiles are possible.

According to a preferred embodiment, the heating device has an electrical resistance heater or a heat pump. Resistance heating enables the generation of heat with the current of the charging point 10th . It is also possible to store energy 50 to be heated by a charge / discharge cycle.

• 1 in schematischer Darstellung einen Ladepunkt und ein am Ladepunkt angeschlossenes Fahrzeug,
• 2 ein Diagramm mit einem Ladestrom,
• 3 eine Tabelle mit schematischer Angabe des maximalen Ladestroms bei einem Energiespeicher entsprechend 2 in Abhängigkeit von der aktuellen Temperatur T (in °C) und dem Ladezustand SOC (in %) des Energiespeichers,
• 4 zwei Kurven für die Ermittlung eines Temperatur-Sollwerts in Abhängigkeit vom Ladezustand, und
• 5 ein Flussdiagramm mit einem Temperaturregler bzw. mit einer Temperatursteuerung.

Further details and advantageous developments of the invention result from the exemplary embodiments described below and illustrated in the drawings, which are in no way to be understood as a restriction of the invention, and from the subclaims. It shows:

• 1 a schematic representation of a charging point and a vehicle connected to the charging point,
• 2nd a diagram with a charging current,
• 3rd a table with a schematic specification of the maximum charging current in an energy storage device accordingly 2nd depending on the current temperature T (in ° C) and the state of charge SOC (in%) of the energy storage,
• 4th two curves for determining a temperature setpoint depending on the state of charge, and
• 5 a flowchart with a temperature controller or with a temperature control.

1 shows a charging point in a schematic representation 10th and one at the charging point 10th connected vehicle 20th . The charging point 10th has a charging point control LP_CTRL 12th which over a line 14 electrical energy can be supplied, and which via a line 16 electrical energy to the vehicle 20th can deliver. Over the lines 14 respectively. 16 a direct current and / or an alternating current can be transmitted in each case. Depending on the application, the term line includes one or more conductors, for example wires, strands or rails.

The vehicle 20th has a loading device 30th which a control device " CTRL " 32 having. The control device 32 is designed to influence the level of the charging current or the level of the charging power of the energy store. For this purpose, the control device 32 preferably a charging current controller, a charging current controller, a charging power controller or a charging power controller, which, for example, individually or together with 33 Marked are.

The control device 32 is over a line 51 with an energy storage " BAT " 50 connected and via a line 53 with other consumers "EQUIP" 52 . The energy storage 50 is over a line 56 with a receiving unit 35 the control device 32 connected, and over the line 56 can store data such as a temperature value T for the Energy storage temperature 50 or a state of charge value SOC (State Of Charge) of the energy storage device.

A connection between two units can also consist of a wireless connection, and spatial separation can be provided, for example between a sensor, an evaluation device for the sensor signal and the control device 32 .

The control device 32 is over a line 55 with a heating device "HEAT" 54 connected, and via the heater 54 can the energy storage 50 Heat can be supplied. The heater 54 can be, for example, an electrical resistance heater, or it can be heated by a charge / discharge cycle of the energy store 50 respectively. In hybrid vehicles that also have an internal combustion engine, the heat of the internal combustion engine can also be used for heating.

The energy storage 50 is preferably a lithium-ion battery or a nickel-zinc battery.

2nd shows a schematic representation of a diagram in which the maximum charging current in A is plotted over time in seconds. Shown is a charging operation in which continuously with a maximum permissible charging current 43 is loaded. The mean 44 of the charging current 43 agrees with the charging current 43 match. The maximum charging current is 10 A, for example, and this value occurs, for example, in a tested energy store 50 at a charge level of 50% and a temperature of -10 ° C.

mit der Ladestromstärke I_L in Ampere (A) der Ladespannung U_L in Volt (V) und der Ladezeit Δt in Sekunden (s). Der griechische Buchstabe Delta (Δ) vor der Ladezeit Δt zeigt, dass es sich bei der Ladezeit um eine Zeitdauer handelt.The charging energy, which can be transmitted in this charging mode in a time interval of 36 s and at a DC voltage of 400 V, is calculated according to the formula $$\begin{array}{c}{\text{E}}_{\mathrm{12th}}={\text{I.}}_{\text{L}}\cdot {\text{U}}_{\text{L}}\cdot \Delta \text{t}=\mathrm{10th}\text{A}\cdot \text{400V}\cdot \text{36s}\\ =\mathrm{144,000}\text{Ws}=40\text{Wh}\end{array}$$

with the charging current I _L in amperes (A), the charging voltage U _L in volts (V) and the charging time Δt in seconds (s). The Greek letter Delta (Δ) before the loading time Δt shows that the loading time is a time period.

3rd shows a table in which it is stated in a simplified _manner which maximum charging current I _{L_max} ( T , SOC ) depending on the current temperature ("Temp.") of the energy storage 50 and depending on the state of charge (" SOC “) Of the energy storage 50 is possible.

• S0: 0-3 A
• S1: 4-10 A
• S2: 11-50 A
• S3: 51-100 A
• S4: 101-200 A
• S5: 201 A und mehr.

The states shown S0 to S5 indicate states in which the maximum permissible charging current I _{L_max is} within the following ranges:

• S0: 0-3 A
• S1: 4-10 A
• S2: 11-50 A
• S3: 51-100 A
• S4: 101-200 A.
• S5: 201 A and more.

Alternatively, the states S0 to S5 can also be defined for electrical power. This is particularly advantageous in the case of charge power control or charge power control.

The energy storage 50 can be charged with charging currents lower than the maximum charging current if, for example, there is a lot of time for charging. In continuous charging operation, however, a charging current _that exceeds the maximum permissible charging current I _{L_max} can lead to destruction or to a dangerous state of the energy store 50 to lead.

It can be seen qualitatively that the maximum charging current increases with increasing temperature of the energy store 50 increases. At a temperature of 50 ° C, the energy storage 50 be charged with high to medium currents until it is full. At a low temperature of -30 ° C, with a charge level of 0% to 20%, charging can take place with a low charging current; from a charge level of 35%, a charging process is hardly possible.

At very low maximum charging currents there is another problem. The power electronics of charging devices often require a minimum _{charging current} I _{L_min} in order to enable a stable charging process. For example, resonance converters with very low charging currents may no longer work stably. With comparatively great effort, the power electronics can be designed to function even with low charging currents. However, this is associated with high costs and greater weight. Expressed mathematically, it can be said that a charging process is only possible if the following applies: $${\text{I.}}_{\text{L}\_\text{min}}<={\text{I.}}_{\text{L}\_\text{Max}}\left(\text{T},\text{SOC}\right)$$

The energy storage can be used to charge even at low temperatures 50 be heated, this leading to additional energy loss by converting electrical energy into heat. This also increases the charging time and the overall charging efficiency deteriorates.

A curve is drawn 70 which, for example, defines a suitable temperature setpoint depending on the state of charge. It can be seen that a temperature setpoint of -10 ° C (range S1 ) to the energy storage 50 continue charging, however, a temperature setpoint of -25 ° C is not (range S0 ).

The temperature setpoint T_S is not constant in the state of charge between 0% and 100%, but runs along the limit at which the maximum charging current on the left side is large enough and on the right side is small or too small.

The control device 32 is preferably designed for the temperature setpoint during a charging process T_S as a function of the state of charge value SOC to be determined in such a way that at the temperature setpoint T_S corresponding temperature of the energy storage 50 and the state of charge value SOC corresponding state of charge of the energy store 50 a charging process is possible, but at least in part at the temperature setpoint T_S the corresponding temperature, a state of charge of 100% cannot be reached. For example, with a state of charge of 50%, there is a temperature setpoint T_S of -10 ° C, but at this temperature charging to 100% is not possible. With a state of charge of 98%, however, the temperature setpoint must be in a range in which a higher state of charge can also be achieved.

The control device 32 is preferably designed for the temperature setpoint during a charging process T_S as a function of the state of charge value SOC to be determined in such a way that at the temperature setpoint T_S corresponding temperature of the energy storage 50 and the state of charge value SOC corresponding state of charge of the energy store 50 a maximum increase in the state of charge of the energy store is possible, which is below 40% of the maximum state of charge. This definition defines the delicacy of the specification or the function. For example, if a temperature setpoint of -10 ° C is specified for a state of charge of 50%, this temperature setpoint is no longer sufficient with a state of charge of 50% + 40% = 90%, but a temperature of at least 10 ° must be there C rule.

The one by the control device 32 predetermined course of the temperature or the temperature setpoint T_S is by arrows 72 indicated. For example, if you start at a temperature of -30 ° C and a charge level of 20%, the temperature setpoint will T_S at a charge level of 35% increased to -25 ° C. At a charge level of 50%, the temperature setpoint T_S increased to -10 ° C. The temperature setpoint is set accordingly T_S along the curve 70 increased until the charging process is terminated, for example after full charging or after charging has been terminated.

Another arrow 74 is shown in which a charging process begins at a charge level of 4% and a temperature of approx. -12 ° C. Because charging is possible in these conditions without the heater 54 To activate, a charging process takes place without heating until a charge level of approx. 50% is reached. Only then will the temperature value T less than the temperature setpoint T_S , and the heater 54 is activated.

• - Die höhere Temperatur führt zu höheren Wärmeverlusten und damit einem geringeren Wirkungsgrad.
• - Die elektrische Energie des Ladepunkts 10 wird für die Erwärmung des Energiespeichers 50 genutzt und steht nicht für den Ladevorgang zur Verfügung. Dies verlängert den Ladevorgang.
• - Wenn der Ladevorgang vorzeitig abgebrochen wird, ist die große Temperaturerhöhung unnötig, da für einen Ladevorgang bei einem niedrigeren Ladezustand eine niedrigere Temperatur ausreichend ist.

In experiments, it has proven to be advantageous to store energy 50 not immediately to a temperature of 50 ° C, for example. On the one hand, a complete charging of the energy store to 100% would be possible at this temperature. On the other hand, this strategy has disadvantages:

• - The higher temperature leads to higher heat losses and thus lower efficiency.
• - The electrical energy of the charging point 10th is used for heating the energy storage 50 used and is not available for the charging process. This extends the loading process.
• - If the charging process is interrupted prematurely, the large temperature increase is unnecessary, since a lower temperature is sufficient for a charging process with a lower state of charge.

4th shows a diagram with a curve 70 and a curve 71 . The curve 70 and the curve 71 give an assignment of the temperature setpoint as a function T_S to the state of charge SOC . The curve 70 corresponds to the curve 70 of 3rd , and it enables energy-saving charging of the energy store 50 . The curve 71 shows an alternative assignment between the temperature setpoint T_S and the state of charge SOC . At the curve 71 is the temperature setpoint T_S higher than the curve 70 , and this makes higher charging currents possible. This is interesting, for example, when the charging point 10th a high charging capacity enables, or if possible, the largest possible charging of the energy store in a short time 50 should be done. If, on the other hand, charging with high efficiency is to take place, the curve is 70 preferable.

The control device preferably 32 the possibility of at least two curves 70 , 71 respectively. provide at least two functions and the loading process one of the curves 70 , 71 or based on functions.

The curves 70 , 71 each have six different temperature values or five levels. Less different temperature values such as three different temperature values can also be selected, or for example 20th different temperature values. It is also possible to specify the function as a mathematical function to be calculated, which can also include additional parameters such as the maximum power of the charging point or the estimated charging time.

The control device 32 is, as shown, preferably designed to match the temperature setpoint T_S to increase the corresponding temperature at least in regions as the state of charge rises. This is advantageous since a higher temperature requires a higher temperature in order to achieve a constant charging current.

5 shows the flow of temperature control in a flowchart.

The routine begins in step S101 , and there is a jump to the step S103 in which the value SOC for the current state of charge of the energy storage 50 is determined. Then in step S105 the temperature setpoint T_S as a function of the state of charge value SOC determined. In step S107 becomes the temperature value T for the current temperature of the energy storage 50 determined. In step S109 the control difference (control deviation) RGL_DIFF is the difference of the temperature value T and the temperature setpoint T_S determined. In step S111 an output value OUT is determined from the control difference RGL_DIFF with the aid of a function g, and the output value OUT is in step S113 spent. Then jump back to the step S103 . The temperature setpoint ( T_S ) is thus continuously at predetermined time intervals as a function of the state of charge value ( SOC ) determined. This can be done before the jump S103 a predetermined period of time can be waited for, or the routine can be called using a timer interrupt, or the routine can be called whenever there is no routine with a higher priority.

The determination of the output value OUT in step S111 can contain, for example, a proportional component, an integral component and a differential component, or, for example, only a proportional component. In addition, a hysteresis can be provided in which the heating device 54 is only switched on when the temperature is below the temperature setpoint by a predetermined minimum amount T_S fell. Additionally or alternatively, it can be provided that the heating device 54 after activation it is only switched off when the temperature T is a predetermined value higher than the temperature setpoint T_S .

The control device 32 is preferably designed at a predetermined temperature T of the energy store 50 the temperature setpoint T_S only increase when the state of charge value SOC has reached a predetermined value. So if, for example, the energy storage 50 has a temperature of 10 ° C, takes place accordingly with an energy store 3rd the charging process from 0% to just under 95% without activation of the heating device 54 instead, and only when the charge level is approximately 95% is the heating device 54 activated.

When the heater is activated 54 If necessary, continuous heating can also take place by increasing or decreasing the current for the heating device accordingly.

Naturally, various modifications and modifications are possible within the scope of the present invention.

In the present controller, the temperature value to be controlled is only influenced via the heating device. If a cooling device is present, it can also be used. However, a higher temperature is generally positive within a given range. The connection of a cooling device is therefore less relevant for the temperature controller, but as a temperature limitation at very high temperatures.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• JP 2010259308 A [0002]
• CN 107317067 A [0003]
• US 2010085019 A [0004]
• WO 2017/099649 A1 [0005]
• GB 254280 B [0006]

Claims (11)

Charging device (30) for charging an energy store (50), in particular for a vehicle (20), which charging device (30) has a control device (32) and a heating device (54), which control device (32) has a receiving unit (35) and a temperature controller (34), which receiving unit (35) is designed to receive a temperature value (T) characterizing the temperature at the energy store (50) and a state of charge value (SOC) characterizing the state of charge of the energy store (50), which control device (32) is designed to receive one Charging to determine the temperature setpoint (T_S) as a function of the state of charge value (SOC), and which temperature controller (34) is designed to control the temperature value (T) to the temperature setpoint (T_S) via the heating device (54). Loading device (30) after Claim 1 , in which the control device (32) is designed to continuously determine the temperature setpoint (T_S) as a function of the state of charge value (SOC) during the charging process at predetermined time intervals. Loading device (30) after Claim 1 or 2nd , in which the control device (32) is designed to increase the desired temperature value at a predetermined temperature of the energy store (50) only when the state of charge value (SOC) has reached a predetermined value. Charging device (30) according to one of the preceding claims, in which the control device (32) is designed to determine the temperature setpoint (T_S) as a function of the charge state value during a charging process such that the temperature setpoint (T_S) in the range of State of charge between 0% and 100% is not constant. Charging device (30) according to one of the preceding claims, in which the control device (32) is designed to determine the temperature setpoint as a function of the state of charge value during a charging process such that at least three for the range of the state of charge between 0% and 100% Different temperature setpoints (T_S) occur, preferably at least six different temperature setpoints (T_S). Charging device (30) according to one of the preceding claims, in which the control device (32) is designed to increase the temperature corresponding to the temperature setpoint at least in regions as the state of charge increases. Charging device (30) according to one of the preceding claims, in which the control device (32) is designed to only activate the heating device (54) for heating during a charging process when the temperature corresponding to the temperature value (T) is lower for the first time than the temperature corresponding to the temperature setpoint (T_S). Charging device (30) according to one of the preceding claims, in which the control device (32) is designed to determine the desired temperature value as a function of the state of charge value during a charging process such that the temperature of the energy store corresponding to the desired temperature value (T_S) (50) and the state of charge of the energy store (50) corresponding to the state of charge (SOC), a charging process is possible, but at least partially at the temperature corresponding to the temperature setpoint (T_S) no state of charge of 100% can be achieved. Charging device (30) according to one of the preceding claims, in which the control device (32) is designed to determine the temperature setpoint (T_S) as a function of the state of charge value (SOC) during a charging process such that the temperature setpoint ( T_S) corresponding temperature of the energy store (50) and the state of charge of the energy store (50) corresponding to the state of charge (SOC), a maximum increase in the state of charge of the energy store is possible, which is below 40% of the maximum state of charge. Charging device (30) according to one of the preceding claims, in which the control device (32) has at least two functions (70, 71) for determining the temperature setpoint (T_S) as a function of the state of charge value (SOC), and in which the control device is designed for this purpose is to enable selection of one of the at least two functions (70, 71) for the charging process. Charging device (30) according to one of the preceding claims, wherein the heating device (54) comprises an electrical resistance heater or a heat pump.

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