DE102010025525A1 - Method of cooling battery packs and battery pack divided into modules - Google Patents

Abstract

The invention relates to a method for cooling battery packs (10), wherein at least one battery pack (10) is divided into a plurality of modules (11) and each module (11) is cooled independently. Furthermore, the invention relates to a battery pack (10), which is divided into modules (11) and wherein each module has at least one cooling device (30, 31, 32, 33).

Description

The The invention relates to a method for cooling battery packs, wherein at least one battery pack is divided into several modules, as well a battery pack, which is divided into modules.

batteries are used in technology in many fields. Goal is one No Power Operation of electrical equipment, such. B. bulbs, Machines or vehicles. In the area of vehicles are high Current densities needed to drive electric motors over long periods periods time. This places high demands on the batteries used and can lead to rapid aging.

The Battery of an electric vehicle is the crucial component for the Range of the vehicle. The battery capacity is limited by the factors battery price, battery weight and available Space. A single battery block, hereinafter also as a module referred to, ideally uses a contiguous space, the only for specific designed for vehicles to disposal stands. A module is made up of a large number of individual battery cells, below just called cells, constructed.

One Another problem is that with a large, generally cooled module, which may comprise 50 or up to several thousand cells, the temperature deviation The cells can be very large with each other. The required Deviation to modules in vehicles, however, is max. 5 K. Every cell equipped with a temperature sensor to control optimal cooling or to be able to regulate is very expensive.

modern Modules are z. B. constructed of lithium-ion batteries. In the state The technology needs every major lithium ion Battery with a temperature monitor equipped be. On the one hand, it should ensure that there are no extreme temperatures during operation be achieved. This is primarily a safer, but also life-time-optimized Operation guaranteed. On the other hand, the aim is to ensure an equalization of cell temperatures be that the cells are all operated similar in temperature. Thereby a different aging is avoided, which leads to a deterioration of the Performance of the battery leads. Ideally, the cell temperatures become substantially the same held at a temperature deviation between cells of 2 to 5 K.

Around a shutdown of the entire battery at too high a temperature too avoid having to continue cooling be provided. This supports also, if properly designed, balancing the temperature over the Battery pack. The typical cooling arrangement in the prior art provides a single cooling circuit, which in the case a temperature control takes into account the temperature of a single cell.

So is z. B. in the small series Tesla Roadster a coherent Battery pack consisting of 6831 pieces of 18650 lithium-ion "high energy" cells, which have a diameter of 18 mm and a length of 65 mm, in housed a steel container. The cells are with a Water-glycol mixture actively cooled. The Vehicle is a two-seater and was designed to be used for the battery pack the space available. Battery pack and vehicle design must be included this solution be consistently coordinated. The Tesla costs about 100 T € and thus offers no cheap solution for the mass market.

At the BMW's Mini E Cooper test vehicle was converted into the rear seat for the battery pack, enough battery capacity to be able to install. The cooling over an air blower. There are 5088 Medium Power 18650 cells in one battery installed. Through this installation solution the space available in the vehicle interior is severely limited.

At the Pilot vehicle call Greenster is the battery, consisting of 180 Cells in 18 modules, divided into several different subunits, these are currently not cooled.

in the GM Volt, a plug-in hybrid, the battery pack is stretched very long designed to fit into the transmission tunnel.

Of the The trend in electric vehicles is clearly moving towards cells with larger capacity. In order to a smaller number of cells in the battery is necessary. It is planned in larger series to be built electric vehicles with lithium-ion cells of size of approx. 10-60 Ah to operate. This reduces the number of cells per vehicle on an order of magnitude 100-500 Cells.

The Modules will become 8-12 Cells in series, with corresponding voltages below 60 V, and one or a few cells connected in parallel. The Mitsubishi "i MiEV", the first Series electric vehicle with lithium-ion cells, used z. B. LEV50 GS Yuasa cells with 50 Ah capacity. 4 cells each connected in series to a module. Out of 24 of these modules, Similarly, all connected in series, the battery pack is 330 V voltage built up.

In the previously described trend to Zel With high power density problems due to heat development of the cells in operation, ie both charging and discharging, to and active cooling is imperative. With increasing heat development, which can occur spatially and temporally differently on cells of the modules, problems such as different aging of the cells are intensified by different thermal conditions.

task It is therefore an object of the present invention to provide a process for improved cooling of battery packs indicating rapid aging of Battery pack counteracts and so to a better durability and cost savings. The possibility a better spatial Distribution of modules of the battery pack is to be created and savings in cooling be made possible by reducing the expenditure on equipment. Furthermore includes the invention a battery pack, which is divided into modules, and improved cooling, allowed with the aforementioned advantages.

The specified task is regarding the method of cooling Battery pack with the features of claim 1 and with respect to Battery packs with the features of claim 8 solved.

advantageous Embodiments of the method for cooling battery packs and in terms of of the battery pack will be apparent from the respective associated dependent claims. The can Features of the main claims among themselves and with features of the subclaims and features of the subclaims among themselves be combined.

The inventive method for cooling of battery packs includes the division of at least one battery pack into several modules, each module being independently cooled.

This allows a division of the battery pack and an arrangement of different Places. Even with different stresses and / or temperatures the individual modules can be cooled by a module corresponding to the module the independent ones cooling each module. This will cause a different aging the module prevents and the battery pack gets its overall performance over one extended Period.

The cooling Each module can vary depending on the temperature of the respective module regulated or controlled done. As a result, a module-specific temperature control or cooling is possible. A sensor can measure the temperature on each module and a regulation or Control, in particular an electronic control or control can according to the measured temperature for each module through Control or control of a cooling device set the temperature. So can all modules are kept at a same temperature.

The cooling a module can be independent of the temperature and / or the cooling other modules of the at least one battery pack. For each can for a Module a cooling device, such as B. a cooling circuit or a fan provided be. This becomes dependent from the temperature of the respective module and independently of the Temperature of other modules regulated or controlled, in particular dependent from the location of the respective module and its ambient temperature.

The cooling A module can also be dependent from the temperature of the module, which is the highest temperature value having. This makes a simplified structure possible, with z. B. only one cooling circuit, its cooling fluid is set at a temperature necessary for cooling the warmest module. As cooling fluids can doing air or liquids like oils, Water or liquid Serve carbon dioxide. As an alternative to the cooling circuit can also be a central Fan controlled according to the temperature of the warmest module or be managed.

The cooling the at least one battery pack can be carried in a vehicle. Then the cooling can at least one module or all modules depending on the particular situation in the vehicle and / or the ambient temperature of the respective Module in the vehicle done.

A cooling the modules of the at least one battery pack can be made that over the entire battery pack a uniform or nearly uniform Temperature exists or arises. This will be the same or similar Aging of all modules of the battery pack allows and overall performance the battery pack improves, in particular its long-term performance.

The battery pack according to the invention is divided into modules and each module has at least a cooling device on. The modular cooling concept allows a division of the total battery into many individual submodules, where each module or a groups of modules with a self-sufficient cooling equipped becomes.

The battery pack or the battery pack is subdivided into many submodules, with preferably 8-12 cells, which are each equipped individually or in smaller subunits with a self-sufficient cooling, which depends on the local Tempe or power consumption of the module can be controlled or controlled. Since the temperature deviation in a small module is significantly smaller than in a large one, there are overall smaller deviations between the modules in the temperature.

The Subdivision of the battery pack into modules enables a distribution of the Modules in the room. The assignment of at least one cooling device per module allows an individually controlled or regulated cooling of each module. This can both dependent from the location or a possible design of the environment and ambient temperature as well as specific performance requirements every module.

Around to enable this For example, each module may include a temperature control device and / or temperature control device exhibit. Alternatively you can all cooling equipment also individually by a central control or regulating device be regulated or controlled.

The at least one cooling device a module can each be independent from a cooling device another module and / or the cooling devices of all the others Be modules. This allows a sensor to measure the temperature at each module and control of each cooling device may be individualized dependent the respective measured temperature.

alternative can a cooling circuit the cooling equipment include, in particular all cooling devices the modules. This means that all cooling devices are connected and give a cooling circuit. It can Be provided valves, in particular control valves, for control or Control of a respective cooling device. So z. B. over the control valves a central cooling fluid flow divided individually according to the temperature of each module and a partial fluid flow is adjusted by a valve, which the respective module cools.

One Each module can be made up of cells. Cells are z. B. single lithium-ion batteries.

It at least one fan, in particular per module, to be provided as an alternative to a cooling circuit, which is formed to the cells of the module with cooling air supply.

The Battery pack can be arranged in a vehicle. Then the modular structure of the battery pack a breakdown of the battery pack on different assemblies or spatial Enable areas of the vehicle. In the places can different temperatures prevail. So z. B. in the Passenger cell have a different temperature than close to a drive unit such as B. an electric motor. The individual cooling by individual cooling devices allows then according to the ambient temperature of a module this too cool, around for all modules of a battery pack z. B. set the same temperature to be able to. This prevents rapid aging of the battery pack.

The advantages associated with the battery pack are analogous to the advantages previously described in relation to the method of cooling battery packs and vice versa.

preferred embodiments the invention with advantageous developments according to the features the dependent claims will be explained in more detail with reference to the figures, but without being limited thereto.

The Figures show:

1 a schematic representation of a battery pack 10 according to the prior art, with cooling device 30 . 31 . 32 . 33 without subdivision into modules, and

2 a schematic representation of a battery pack according to the invention 10 , divided into modules 11 each with a temperature sensor 41 for regulation 40 a cooling device 30 . 31 . 32 . 33 , and

3 a battery pack 10 , as in 2 is shown, but with control valves 42 to other modules 11 independent cooling of each module 11 , and

4 a battery pack 10 , as in 2 is shown, but with completely separate, independent cooling devices 31 . 30 . 32 . 33 per module 11 , and

5 a module 11 which has a fan 33 is cooled independently of other modules.

In 1 is a battery pack 10 with cooling device 30 . 31 . 32 . 33 represented according to the prior art. The battery pack 10 includes n battery cells 20 where n is a natural number. So z. B. a battery pack in a motor vehicle consist of about 20,000 cells. These can then in a kind of battery pack at a location in the vehicle, eg. B. be accommodated in the trunk.

In order to avoid shutdown of the entire battery at too high a temperature must continue cooling is provided. This, if properly designed, also helps balance the temperature across the battery pack 10 , The typical prior art cooling arrangement provides a single cooling circuit 30 before, which takes into account the temperature of a single cell in the case of a temperature control.

The cooling device or cooling arrangement comprises a coolant connection 31 to the battery pack 10 which z. B. can be realized by a heat exchanger or a cooling plate. A cooling circuit 30 connects the coolant connection 31 with an active or passive recooling unit 32 , This can, for. B. include a heat exchanger or a cooling plate, which can give off heat to the ambient air. A coolant circulation 33 can be in the form of a pump or a blower in the cooling circuit 30 be realized, and ensures a transport of the coolant in the cooling circuit 30 from the coolant connection 31 to the recooling unit 32 and back again. As a coolant or cooling fluid, air, oils, water or other liquid and gases may be used which have a high heat coefficient, such. As liquid carbon dioxide or air.

In 2 is a battery pack according to the invention 10 shown in which the battery cells 20 in different places z. B. in a vehicle, in modules 11 are distributed in a group. Every module 11 has its own coolant connection 31 and its own temperature sensor 41 on. The individual coolant connections 31 the modules 11 are about a common cooling circuit 30 connected together, in particular thermally via a cooling fluid, which in the cooling circuit 30 flows. About the coolant connection 31 the cooling fluid absorbs heat amount of the modules 11 and leads to a cooling of the modules 11 , The cooling fluid flows through the cooling circuit 30 to at least one recooling unit 32 , At the recooling unit 32 the coolant returns the absorbed heat partially or completely to the environment, z. B. to the ambient air. A coolant circulation 33 , z. As a pump or a fan, holds the cooling fluid or coolant in the cooling circuit 30 in motion, allowing the cooling fluid from the recooling unit 32 back to the coolant connections 31 the modules 11 can flow.

The temperature of the modules 11 or the flow rate of the cooling fluid and / or at the recooling unit 32 Dissipated heat can be controlled by a temperature controller 40 be managed. The regulation may vary according to the temperature sensor 41 with the highest measured temperature value. This ensures that the cooling fluid can absorb enough heat to all the modules 11 to cool or maintain below a critical temperature value. The temperature controller 40 Among other things, the flow velocity and thus the cooling capacity of the cooling circuit 30 regulate the performance of the coolant circulation (eg pump, blower) depending on the temperature sensors 41 measured temperatures is controlled. Alternatively or additionally, the at the recooling unit 32 amount of heat emitted are controlled by the temperature controller 40 ,

In 3 is an alternative embodiment of the refrigeration cycle 30 represented according to the invention. The coolant connections 31 the modules 11 are not like in 2 in the cooling circuit 30 fluidly connected in series, but in parallel in the cooling circuit 30 fluidly connected. The modules 11 can be distributed again at different locations in a vehicle and from a branched cooling circuit 30 be supplied with cooling fluid. A regulation of the coolant flows in each case to a module 11 takes place for. B. over a module 11 respectively associated control valve 42 , Every module 11 has at least one temperature sensor 41 on, the individual temperature of the module 11 z. On the temperature of a cell 20 or averaged by cells 20 measures. A temperature controller 40 regulates the control valve depending on the measured temperature 42 for the coolant connection 31 of the respectively assigned module 11 , As a result, the proportion of cooling liquid of the cooling circuit 30 regulated or determined which of the coolant connection 31 of the assigned module 11 is supplied and thus the dissipated amount of heat to the module 11 ,

Alternatively, instead of temperature controllers 40 , each one module 11 are assigned, a central controller z. B. be provided with a computer, which the respective control valves 42 controls depending on the modules 11 with the temperature sensors 41 each measured temperatures. By the structure described above, the mechanical complexity of the cooling can be reduced and the uniformity of the cell temperatures can be increased.

In 4 is a battery pack according to the invention 10 illustrated in which each module has a separate, from the other cooling circuits 30 separate cooling device comprises. The battery pack 10 is in modules as in the previously described embodiments of the invention 11 divided and the modules 11 are each at different locations z. B. distributed in a vehicle. Every module 11 has its own, separate from the other cooling circuit 30 on, and is supplied via this with cooling fluid. The cooling circuit in turn has a respective recooling unit 32 and a coolant circulation 33 on which fluidly through the cooling circuit 30 with the coolant connection 31 a module 11 are connected. This will not only be a spatial distribution of the modules 11 , but also the associated coolant circuits 30 or complete cooling facilities possible. Every cooling circuit 30 is by a the respective module 11 associated temperature sensor 41 and the associated temperature controller 40 regulated. Alternatively, a central control unit for all modules 11 z. B. be provided in the form of a computer.

Alternative to a fluid circuit 30 can also be a fan or fan for cooling 33 serve, which each directly on the module 11 is attached and this cools, depending on the on the module by the respective temperature sensor 41 measured temperature and regulated by the respective controller 40 , This is exemplary in 5 shown. In this case, the cooling with air is particularly favorable because each unit or each module 11 equipped with a fan, a simple structure allows. In the in 5 shown embodiment, a module 11 comprising 3 cells 20 , via a fan as coolant circulation 33 supplied with fresh air. The fresh air serves as a coolant. The individual control reduces the mechanical complexity of the cooling to a minimum and increases the uniformity of the cell temperatures.

The exemplary embodiments described above only give examples of individual possibilities of constructing the battery pack according to the invention 10 and the implementation of the method according to the invention. Combinations of the embodiments described above, in particular in the figures are also possible.

The division of the battery pack 10 in modules 11 with its own cooling allows flexible adaptation of the battery pack 10 to the respective installation space situation and a distribution into suitable installation spaces. The self-contained cooling is together with the local temperature control per module 11 important to a consistent life of all cells 20 and modules 11 within z. B. a vehicle, in particular a motor vehicle such. B. to guarantee automobile. A uniform life is only about a nearly constant temperature of all modules 11 to reach. At the same time, the cooling capacity for different battery modules 11 within z. B. a vehicle depending on the installation location and the respective ambient temperature can be set differently. Thus, despite different ambient temperatures (eg location in the vehicle or heating by ambient conditions), a more consistent lifetime of all cells can be achieved and possibly save energy.

In addition, by the representation of the battery or the battery pack 10 in individual blocks or modules 11 an optimized weight distribution on the axles / wheels z. B. easier to reach in a vehicle.

• – die einmal ausgelegten Batteriemodule 11 können für verschiedene Fahrzeuge eingesetzt werden
• – das Packaging im Fahrzeug lässt sich günstiger gestalten
• – da im Falle eines Aufpralles oder eines „Thermal Runaway” nur kleine Einheiten betroffen wären, steigt die Sicherheit
• – die Antriebsleistung der Kühlung sinkt, da räumlich und zeitlich begrenzt die Kühlung aktiviert werden kann
• – geringerer Entwicklungsaufwand der Batterie
• – es ist eine ”Plug and Play” Lösung mit den Einzelmodulen denkbar, da diese alle autarke Einheiten sind.

Further advantages of the invention for z. B. a vehicle are:

• - the once designed battery modules 11 can be used for different vehicles
• - The packaging in the vehicle can be cheaper
• - In case of an impact or a "thermal runaway" only small units would be affected, the safety increases
• - The drive power of the cooling decreases, since spatially and temporally limited the cooling can be activated
• - Lower development costs of the battery
• - It is a "plug and play" solution with the single modules conceivable, since these are all self-sufficient units.

It is ideally just a connection of the main current path through All modules and a control line to the master BMS needed.

Claims (14)

Method for cooling battery packs ( 10 ), wherein at least one battery pack ( 10 ) into several modules ( 11 ), characterized in that each module ( 11 ) is cooled independently. Method according to claim 1, characterized in that the cooling of each module ( 11 ) depending on the temperature of the respective module ( 11 ) is regulated or controlled. Method according to one of the preceding claims, characterized in that the cooling of a module ( 11 ) regardless of the temperature and / or cooling of other modules ( 11 ) of the at least one battery pack ( 10 ) he follows. Method according to claim 1 or 2, characterized in that the cooling of a module ( 11 ) depending on the temperature of the module ( 11 ), which has the highest temperature value. Method according to one of the preceding claims, characterized in that the cooling of the at least one battery pack ( 10 ) takes place in a vehicle. Method according to claim 5, characterized in that the cooling of at least one module ( 11 ) or all modules ( 11 ) depending on the respective position in the vehicle and / or the ambient temperature of the respective module ( 11 ) he follows. Method according to one of the preceding claims, characterized in that a cooling of the modules ( 11 ) of the at least one battery pack ( 10 ) is carried out so that over the entire battery pack ( 10 ) a uniform or nearly uniform temperature exists or arises. Battery pack ( 10 ), which in modules ( 11 ), characterized in that each module ( 11 ) at least one cooling device ( 30 . 31 . 32 . 33 ) having. Battery pack ( 10 ) according to claim 8, characterized in that each module ( 11 ) a temperature control device ( 40 ) and / or temperature control device ( 40 ) having. Battery pack ( 10 ) according to claim 8 or 9, characterized in that the at least one cooling device of a module ( 11 ) each independently of a cooling device of another module ( 11 ) and / or the cooling devices of all other modules ( 11 ). Battery pack ( 10 ) according to claim 8 or 9, characterized in that a cooling circuit ( 30 ) comprises the cooling devices, in particular all the cooling devices of the modules ( 11 ), and valves ( 42 ) are provided, in particular control valves ( 42 ), for controlling or regulating a respective cooling device. Battery pack ( 10 ) according to one of claims 8 to 10, characterized in that a module ( 11 ) each from cells ( 20 ) is constructed. Battery pack ( 10 ) according to claim 12, characterized in that at least one fan ( 33 ) in particular per module ( 11 ) is provided, which is formed the cells ( 20 ) of the module ( 11 ) with cooling air to supply. Battery pack ( 10 ) according to one of claims 8 to 13, characterized in that the battery pack ( 10 ) is arranged in a vehicle.

Images