DE102017202391A1 - Method for cooling a battery, battery, vehicle with battery and charging device for charging and cooling a battery - Google Patents

Abstract

The present invention provides a method of cooling a battery, particularly a traction battery, preferably in a vehicle, wherein the battery is configured to be charged at a battery charging temperature. The method is characterized in that cooling medium having a boiling temperature which is lower than the battery charging temperature and / or in the range of 10 to 50 °, preferably in a range of 20 to 40 °, is at least partially supplied to the battery in the liquid state of aggregation ,

Description

Technical area

The invention relates to a method for cooling a battery, in particular a traction battery, wherein the battery is charged at a battery charging temperature. Aside from the battery as such, the invention also relates to a vehicle having a battery and a charging device for cooling and charging the battery.

State of the art

Batteries and charging devices of the type mentioned are widely used in the field of electric vehicles or hybrid vehicles. Such batteries generally have a plurality of battery cells that are electrically connected together.

In general, when charging batteries, high current heat losses may occur, resulting in exceeding the allowable operating temperature range of the battery, resulting in a corresponding reduction in power. The conventional cooling systems for cooling traction batteries are not sufficient, for example, to be able to dissipate the resulting amount of heat without delay in a fast charge.

In the forefront of traction battery systems is the high energy density to allow a long range. Often there is a relatively high internal cell resistance, which leads to high heat loss during unloading (while driving) and when charging the battery. In particular, during fast charging, it may therefore come to an exceeding of the permitted operating temperature range of the battery.

The problem is revealed by this problem DE 44 08 961 C1 a method for cooling a traction battery during a charging process on a charging device, wherein the traction battery is cooled when charging the charging device to reduce the associated with the charging of the battery heat generation in the battery. Therein is also disclosed that cooling water can be used, which is supplied to the battery from the charging device and then returned from the battery via a return line into the charging device.

Such cooling mechanisms have proven themselves. However, ever higher demands are placed on the cooling performance, especially if a fast charging of the battery is desired. For example, it is intended to reduce the load time to less than 6 minutes.

Presentation of the invention

It is therefore an object of the present invention to improve the cooling of a battery with a simple design. Also, a corresponding charging device should be provided.

At the same time, changes to be made to the battery for it should be kept as low as possible, so that the energy density and the power density of a battery remain essentially the same.

This object is achieved by the method for cooling a battery having the features of claim 1. Accordingly, a method for cooling a battery, in particular a traction battery, which may be arranged in particular in a vehicle, is provided, wherein the battery is arranged to be charged at a battery charging temperature. Cooling medium having a boiling temperature which is lower than the battery charging temperature and / or in the range between 10 and 50 °, preferably in a range of 20 to 40 °, is at least partially supplied in the liquid state of aggregation of the battery, in particular introduced into the battery.

Furthermore, a battery, preferably a traction battery, is preferably provided for a vehicle, according to claim 5, wherein the battery is arranged to be charged at a battery charging temperature by means of a charging device. The battery has at least one connection unit which is set up, cooling medium having a boiling temperature which is lower than the battery charging temperature and / or in the range between 10 and 50 °, preferably in a range of 20-40 °, in the liquid state of aggregation Cooling of the battery, in particular when charging the battery, supply, wherein the battery is free of a return for returning coolant to the charging device.

Furthermore, a vehicle with a battery according to the invention is provided according to the invention.

In addition, according to claim 13, a charging device is being considered, specifically for charging and cooling a battery, in particular a traction battery, wherein the charging device is preferably stationary or mobile. In this case, the charging device has a device-side power connection for supplying the battery with power when charging the battery and a cooling connection for supplying cooling medium having a boiling temperature which is lower than the battery charging temperature and / or in the range between 10 and 50 °, preferably in a range between 20 to 40 °, is in the liquid state of aggregation to the battery.

Usually, the battery charging temperature is in a range between 10 and 50 °, preferably in a range of 20 to 40 ° C. When the outside temperature is lower, the battery charging temperature can be set to 10 or 20 °, whereas when the outside air is hot, the battery may be at 40 or 50 ° C when charging. Within this range, where the battery charging temperature may be, the battery will not be damaged during charging or can be charged efficiently. Thus, the battery charging temperature is understood in particular to mean the temperature which the battery can accept when charging, without leaving the range of the permitted operating temperature of the battery.

So that the phase transition from the liquid state of aggregation to the gaseous state during cooling of the battery can be exploited, the boiling temperature of the cooling medium can be below the temperature that the battery occupies when charging, ie below the battery charging temperature.

The normal boiling temperature of a fluid is understood to mean the boiling point which the fluid has at normal pressure, namely at 1 bar. The boiling temperature can therefore be the normal boiling temperature. In the present case, it is also conceivable that the cooling medium is pressurized, which increases the boiling point.

As a cooling medium, for example, liquid CO ₂ , which is pressurized serve. The normal boiling point of CO ₂ is -78.48 ° C and correspondingly higher at pressure build-up. Other cooling media, in particular cryogenic liquids, for example nitrogen, are also conceivable.

The invention is based on the idea optimally exploit the evaporative cooling by a phase transition of the cooling medium takes place, from liquid to gaseous. This change in the state of aggregation of the cooling medium requires the application of heat of vaporization, which must be removed from the battery, which makes the cooling of the battery even more efficient. Cooling medium is thus supplied in the liquid state of aggregation of the battery and characterized in that the boiling temperature of the cooling medium is below the temperature that occupies the battery when charging, a phase transition of the cooling medium takes place when charging the battery. Characterized in that a phase transition takes place in the cooling medium during cooling of the battery, the amount of heat that can be withdrawn from the battery, greater than if the cooling medium would be used without phase transition for cooling the battery. In addition, there is no problem with liquid cooling medium, which may remain undesirable in the battery after charging and cooling, since the cooling medium is substantially no longer liquid, but gaseous.

The battery according to the invention, to which cooling medium can be supplied via a connection unit, is free from a return for returning cooling medium into the charging device, since cooling medium performs a phase transition during cooling of the battery, so that after liquid cooling medium has been brought into contact with the battery, essentially only cooling medium in the gaseous state is present, which can easily escape into the ambient air. A return for returning liquid cooling medium in the charging device is therefore not necessary. It is thus provided an open circuit. Cooling medium is thus supplied from the charging device during charging in liquid form and will escape after cooling from the battery in the gaseous state in the ambient air. Characterized in that the battery is free of a return for returning the cooling medium in the charging device, the battery can be made simpler. In particular, no collecting of cooling medium is necessary, which has already contributed to the cooling of the battery. There is therefore no need to design a complex return.

The charging device according to the invention must accordingly have a power connection for supplying the battery and a cooling connection for supplying cooling medium. In this case, the cooling connection must be set up so that cooling medium having a boiling temperature which is lower than the battery charging temperature and / or in the range between 10 and 50 °, preferably in a range of 20 to 40 °, can be added.

Particularly advantageous developments of the invention are specified in the dependent claims.

Although it is preferred to provide the method for cooling the battery when charging the battery, however, the present invention is not limited thereto. For example, it is also conceivable that the cooling according to the invention is carried out after a particularly sporty driving style, where the battery has been deprived of much power.

Preferably, the cooling medium is thus introduced at least temporarily during the charging of the battery. As a result, the heat loss that occurs when charging the battery in the battery, at least partially faster and better dissipated. As a result, for example, the battery can be charged faster, which is associated with persistently high current heat losses, where otherwise the operating temperature range of the battery would be exceeded. For example, then the battery within a few minutes, for example 6 minutes, to be fully charged.

In the method according to the invention, the cooling medium is preferably transferred from the liquid state of aggregation to the gaseous state of aggregate during cooling of the battery. The transition from the liquid to the gaseous state of aggregation should thus in particular not already take place when the cooling medium is supplied to the battery, but it is to be ensured that the phase transition takes place directly when the battery is in contact and thus the heat of vaporization of the battery is withdrawn.

More preferably, the battery is configured such that cooling medium receives heat from the battery at the location of the phase transition. Accordingly, it can be ensured that the battery is cooled by utilizing the heat of vaporization to be applied and the battery is not cooled only by heat exchange with the cooling medium without changing the state of aggregation. This can be done for example by selecting a suitable cooling medium or by pressurizing the cooling medium.

The battery according to the invention preferably has at least one distribution device for distributing cooling medium at least in sections along the battery, wherein the distribution device is connected directly or indirectly to the connection unit. It can thus be achieved that cooling medium becomes accessible to different, in particular all, regions of the battery.

Further preferably, the battery has lines for conducting cooling medium from the distributor to individual cells of the battery. It can thereby be achieved that cooling medium can be fed directly to cells of the battery, and in particular the battery can be cooled "from the inside" directly to the cells of the battery where the heat is generated.

In principle, the distributor device could be arranged on an outer side of a battery housing. Preferably, however, the battery has lines which are arranged within a battery housing, so that cooling medium can be fed directly via the lines to individual cells of the battery. A further advantageous embodiment is therefore such that the battery has a housing which has an opening which is adapted to deliver gaseous cooling medium to the environment, preferably to the ambient air. Preferably, the opening is adapted to be gas permeable and liquid impermeable. The opening may also be arranged in the housing such that when the battery is arranged in the vehicle, the opening is formed on top of one side of the housing. Characterized in that the battery has a housing which surrounds the battery substantially completely, an opening in the housing must be provided so that cooling medium, which is gaseous after the heat absorption of the battery, does not "jam" in the housing, but again the environment can escape, preferably to the ambient air. This opening is adapted to deliver gaseous cooling medium and in particular not configured to discharge liquid cooling medium. The orifice may be configured to be gas permeable and liquid impermeable, which may be achieved, for example, by a membrane (eg, Goretex membrane). Moreover, when the opening in the housing is arranged such that when the battery is disposed in the vehicle, the opening is formed at the top of one side of the housing, it can be better prevented that liquid (e.g., water) enters the battery from the outside.

For example, in the case where CO _{2 is used} as the cooling medium, after the battery is cooled, there is gaseous CO ₂ in the battery. Since CO ₂ in the gaseous state is heavier than air (it has a specific gravity to air of 1.529), after the supply of liquid cooling medium is completed, the state that the battery in the case becomes substantially CO ₂ will be set in the battery Gas remains filled until just below the opening. The fact that gaseous CO ₂ accumulates in the battery case and also remains largely after completion of the charging and cooling process, this can act as a fire retardant and can thus for safety when charging the battery, especially during initial charging when no liquid cooling medium is supplied , but also to the operation of the vehicle, without the battery is cooled, contribute to safety.

In a preferred embodiment, the battery has at least one nozzle, and optionally also a plurality of nozzles. The nozzle (s) is / are preferably arranged on the distributor, and they can each be arranged on a line. The nozzle serves to deliver cooling medium to the battery or cells of the battery. Through the nozzle liquid cooling medium can be distributed in droplet form and so a larger area of the battery to be cooled.

Further preferably, a fan distributor is arranged on a nozzle, which allows the cooling medium is uniformly and finely distributed over the battery or the cells, so that a correspondingly uniform cooling of the battery or the individual cells is possible. Preferably, a fan distributor is arranged on each nozzle.

The battery may have a battery-side power connection for charging the battery, wherein the battery-side power connection and the supply for supplying cooling medium are at least partially integrated in a battery-side charging plug. By integrating the power connector and supplying coolant, it is easy to handle when charging and cooling the battery.

In the charging device according to the invention, the device-side power connection and the cooling connection can be arranged together in a device-side charging plug. In other words, the device-side power connection and the cooling connection may be integrated in a device-side charging connector. This can be given a simple handling when charging the battery by the charging device.

Furthermore, the charging device is preferably free of a discharge for discharging cooling medium, which has been supplied via the cooling connection of the battery. Since the cooling medium is present in gaseous form after evaporation when cooling the battery, it does not have to be returned to the charging device, but can escape freely into the environment. Since such a discharge is not necessary, the loading device can be made simpler.

The charging device may include a tank for holding cooling medium in liquid state. This has the advantage that no continuous connection of the charging device to a supply of cooling medium must be provided. Cooling medium does not have to be taken from a continuous supply, but the charging device can be designed as a separate part, which is designed independently of a supply system with cooling medium. This allows the loading device to be positioned in a variety of ways.

Other features and advantages of the invention will become more apparent from the following detailed description.

list of figures

• 1 shows a battery according to the invention in a first embodiment;
• 2 shows a battery according to the invention in a second embodiment;
• 3 shows a battery according to the invention in a third embodiment;
• 4a shows a battery-side charging plug;
• 4b shows a cross-sectional view of a battery-side charging plug;
• 5a shows a loading device according to the invention;
• 5b shows a cross-sectional view of a device-side charging plug of a charging device.

Detailed description of preferred embodiments

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

1 shows a battery 1 containing multiple cells 1a . 1b , 1c, ..., 1n. The cells can touch each other in one direction in the battery 1 be arranged. These are arranged side by side so that + and - poles are connected to each other. The electrical line 9 connects the individual cells 1a . 1b . 1c , ..., 1n together.

The battery 1 is preferably a traction battery, which is arranged in a vehicle. The vehicle may be an electric vehicle or a hybrid vehicle. There can be any number of battery cells in the battery 1 be provided, for example, N-cell modules.

The battery 1 has a connection unit 8th in which is arranged, cooling medium having a boiling temperature which is lower than the battery charging temperature and / or in the range between 10 and 50 ° C, preferably in a range of 20-40 ° C, in the liquid state for cooling the battery, in particular when charging the battery. At the connection unit 8th can the feeder 2 be attached by the connection unit 8th to a battery-side charging plug 7 leads. The battery according to the invention 1 is free from recirculation to return coolant to the loader. The battery 1 shows the case 12 on top of that, the battery 1 essentially completely surrounds. Furthermore, an opening 13 be provided in the housing, wherein the opening 13 is set up to deliver gaseous cooling medium to the environment, ie the ambient air. As in 1 shown is the opening 13 at the top of the battery case 12 formed, in the illustrated embodiments, at the top of the side of the housing 13 , The opening 13 may be configured to be gas permeable and liquid impermeable.

In 1 the battery has a distributor 3 on, for distributing cooling medium at least in sections along the battery 1 serves. Here is the distribution device 3 in particular for distributing cooling medium in the longitudinal direction of the battery 1 , The distribution device 3 is direct or indirectly with the connection device 8th connected. The distribution device 3 can be a distributor plate.

In the 1 illustrated battery has a plurality of nozzles 5a , 5b, 5c, ..., 5n, along the longitudinal direction of the distributor 3 are arranged at this. So can cooling medium from the distributor 3 be atomized via the nozzle (s). A nozzle 5a can each be for a cell 1a be provided. The spray 10 gets from each of the nozzles 5 delivered to the battery 1 optimally be able to apply cooling medium.

In the in 2 shown embodiment is additionally a line 4 provided, differing from the distribution device 3 to the cells 1a . 1b . 1c , ..., 1n the battery extends. The administration 4 includes several lines 4a . 4b . 4c , ..., 4n for conducting cooling medium from the distributor to the individual cells. The nozzles 5a . 5b , 5c, ..., 5n can each be on a line 4a . 4b . 4c , ..., 4n be arranged. By doing that, lines 4 from the distributor 3 to the nozzle 5 extend, a diverse structure is possible. One module can be used per module cell 5 be provided.

For better distribution can also be a fan distributor 11 can at the nozzle 5 be provided, in particular a fan distributor 11 per nozzle 5 , such as in 2 indicated.

In the in 3 the embodiment shown is the distributor 3 in the other side of the battery 1 arranged, that is, the distribution device 3 is essentially the electrical wiring 9 opposite, so the electrical cells 1a . 1b . 1c , ..., 1n between the electrical wires 9 to which the electrical cells are connected, and the distribution device 3 lie. The individual cells are thus acted upon by cooling medium from one side and are electrically connected to one another on another side, namely the opposite side. In the 1 and 2 In contrast, embodiments are shown in which the electrical lines 9 on the same side of the electrical cells 1a . 1b . 1c , ..., 1n like the distribution device 3 are arranged.

4a shows a section of the feeder 2 as well as the battery-side charging plug 7 , In the cross-sectional view in 4b of the charging plug 7 are the two battery-side power connections 6 as well as the feeder 2 shown for supplying cooling medium. The battery side charging plug 7 thus has a battery-side power connection 6 to charge the battery integrated with the feeder 2 for supplying cooling medium.

When cooling the battery 1 Coolant is in the liquid state of aggregation in the battery 1 introduced, and preferably when charging the battery. The cooling medium is initially via the charging plug 7 about the feeder 2 to the connection unit 8th guided. Cooling medium is then through the distributor 3 and the nozzles 5 on the individual module cells 1a . 1b . 1c , ..., 1n applied and preferably proceeds on the surface of the cell modules from the liquid state of aggregation in the gaseous state of aggregation. In the transition from one state of aggregation to the other, heat of vaporization necessary for the phase transition is extracted from the battery cells, so that the individual battery cells can be efficiently cooled. The cooling medium thus absorbs heat from the battery or the module cells at the location of the phase transition.

In 5a is the charging device according to the invention 14 for charging and cooling the battery 1 shown. The loading device 14 is in the in 5a shown embodiment arranged stationary.

Alternatively, the charging device 14 but also be mobile and be arranged for example in a service vehicle. Such an emergency vehicle (not shown) can be used, for example, when a stagnant vehicle (whose battery is empty) has to be charged on site in order to continue driving. On the emergency vehicle, the charging device may be arranged, which is provided with a motor unit or with fuel cells, and a tank for holding cooling medium in the liquid state of aggregation.

The loading device 14 has a device side power connection 15 to supply the battery with power when charging the battery and a cooling connection 16 for supplying cooling medium having a boiling temperature which is lower than the battery charging temperature and / or in the range between 10 and 50 °, preferably in a range of 20 to 40 °, in a liquid state. This is in 5b shown where the cross section through the charging plug 17 with the two power outlets 15 and the cooling connection 16 is shown. The device side power connection 15 and the cooling connection 16 So are together in a device-side charging plug 17 arranged.

The loading device 14 is free of a discharge for the discharge of cooling medium, which is via the cooling connection 16 the battery 1 has been supplied. The loading device 14 has a tank 19 for holding cooling medium in the liquid state of aggregation. The loading device 14 is connected to the electricity grid via the connection 21 connected. The Tank 19 turn is with the cable 18 connected to the supply of cooling medium, which in turn into the cooling connection 16 empties. The connection 20 is used for filling with cooling medium and is with the tank 19 connected.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely 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.

Cited patent literature

• DE 4408961 C1 [0005]

Claims (16)

Method for cooling a battery (1), in particular a traction battery, preferably in a vehicle, wherein the battery is arranged to be charged at a battery charging temperature, characterized in that cooling medium having a boiling temperature which is lower than the battery charging temperature and / or Range between 10 and 50 °, preferably in a range of 20 to 40 °, is supplied in the liquid state of aggregation at least in sections, the battery (1). Method according to Claim 1 , characterized in that cooling medium is supplied at least temporarily during charging of the battery (1). Method according to Claim 1 or 2 , characterized in that cooling medium passes during cooling of the battery (1) from the liquid state of aggregation to the gaseous state of aggregation. Method according to Claim 3 , characterized in that cooling medium at the location of the phase transition receives heat from the battery. Battery (1), in particular traction battery, preferably for a vehicle, wherein the battery is adapted to be charged at a battery charging temperature by means of a charging device, and the battery has at least one connection unit (8) which is arranged, cooling medium having a boiling temperature, the is less than the battery charging temperature and / or in the range between 10 and 50 °, preferably in a range of 20 to 40 °, is to supply in the liquid state of aggregation of the battery for cooling the battery, in particular when charging the battery, the battery free from a return for returning cooling medium, in particular in the liquid state of aggregation, into the charging device. Battery after Claim 5 , characterized in that the battery has at least one distribution device (3) for distributing cooling medium at least in sections along the battery (1), wherein the distribution device (3) is directly or indirectly connected to the connection unit (8). Battery after Claim 5 or 6 , characterized in that the battery (1) lines (4a, 4b, ..., 4n) for guiding cooling medium from the distributor (3) to individual cells (1a, 1b, ..., 1n) of the battery (1 ). Battery after one of the Claims 5 to 7 , characterized in that the battery has a housing (12) which has an opening (13) which is set up to deliver gaseous cooling medium to the environment, preferably to the ambient air, the opening (13) preferably being set up in such a way that it is gas-permeable and liquid-impermeable, and / or the opening (13) in the housing is arranged such that when the battery (1) is arranged in the vehicle, the opening in the housing above, in particular on one side of the housing is formed. Battery after one of the Claims 5 to 8th , characterized in that it is at least one nozzle (5), preferably a plurality of nozzles (5a, 5b, ..., 5n), which is preferably on the distributor (3) is / are arranged and further preferably each on a line (4a , 4b, ..., 4n) for discharging cooling medium to the battery. Battery after Claim 9 , characterized in that a fan distributor (11) is arranged on a nozzle (5), preferably on each nozzle. Battery after one of the Claims 5 to 10 , characterized in that it comprises a battery-side power connection (6) for charging the battery, wherein the battery-side power connection (6) and the supply (2) for supplying cooling medium are at least partially integrated in a battery-side charging plug (7). Vehicle with a battery after one of the preceding ones Claims 5 to 11 , A charging device (14) for charging and cooling a battery (1), wherein the charging device is preferably stationary, the charging device having a device side power connection (15) for supplying the battery (1) with power when charging the battery and a cooling connection (16) to the battery Feeding of cooling medium having a boiling temperature which is lower than the battery charging temperature and / or in the range between 10 and 50 °, preferably in a range of 20 to 40 °, is in the liquid state of aggregation to the battery. Charger after Claim 13 , characterized in that the device-side power connection (15) and the cooling connection (16) are arranged together in a device-side charging connector (17). Charger after Claim 13 or 14 , characterized in that the charging device is free of a discharge for the discharge of cooling medium, which has been supplied via the cooling connection (16) of the battery. Charger after Claim 13 . 14 or 15 , characterized in that the loading device a tank (19) for holding cooling medium in the liquid state.

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