Fast charging method for a battery module

Abstract

Fast charging method for a battery module (100), comprising a heat busbar (107) which thermally contacts at least one battery cell (103) of the battery module (100), comprising the following steps a. Cooling (610) of a cooling device to a temperature below 0 °C, b. Charging (630) of the battery module (100), and c. thermally conductive contact (640) of the cooling device with the heat busbar (107) of the battery module (100), wherein the battery module (100) at least a. a battery cell (103), b. a first contact element (101) which electrically and thermally contacts a first pole (104) of the battery cell (103), c. a second contact element (102) which electrically and thermally contacts a second pole (105) of the battery cell (103), d. at least one electrically insulating insulation area (106, 106a, 106b), wherein the insulation area (106, 106a, 106b) thermally contacts the first contact element (101) and / or the second contact element (102), and e. the heat busbar (107) having a heat busbar, wherein the heat busbar (107) indirectly thermally contacts the first contact element (101) and the second contact element (102) via the at least one insulation area (106, 106a, 106b), whereby the battery module (100) is equipped by means of the heat busbar (107) to supply or remove heat to the battery cell (103) via the first pole (104) and via the second pole (105).

Description

[0001] The invention relates to a fast charging method for a battery module with heat-dissipating electrical contacts. State of the art

[0002] German patent application DE 10 2010 055 600 A1 describes a device for cooling a battery composed of a plurality of individual battery cells. Discrete thermal conductivity elements are arranged in the area of ​​the individual battery cells or between the individual battery cells.

[0003] German patent application DE 10 2013 216 941 A1 describes a capacitor arrangement comprising a capacitor and an associated cooling element. The at least one cooling element is in direct mechanical and thermal contact with the capacitor body, but not in electrical contact with the metal layers arranged therein.

[0004] German patent application DE 10 2012 018 113 A1 discloses a battery consisting of a plurality of pouch cells, each pouch cell having a terminal for the positive terminal and a terminal for the negative terminal. The battery also includes a circuit board which incorporates contact tabs on its sides as low-voltage arresters for the individual battery cells. The arrester tabs and the contact tabs of the circuit board are additionally connected to a cooling plate. To prevent electrical short circuits, a thermally conductive film, which conducts heat well but is electrically insulating, is inserted between the arrester tabs and the cooling plate.

[0005] Document DE 10 2014 212 143 A1 discloses a contacting device for contacting an energy storage cell with at least one circuit board.

[0006] German patent application DE 10 2011 086 130 A1 discloses a battery for a vehicle with at least one battery cell and at least one conductor for electrically contacting the battery cell and a heat sink, which is connected to the heat transfer surface of the at least one conductor by means of an electrically insulating and thermally conductive adhesive film.

[0007] German patent application DE 10 2014 221 870 A1 discloses a battery comprising a plurality of battery cells connected in series or parallel, each having a cell casing and an anode area and a cathode area protruding from the cell casing, wherein the anode areas and cathode areas of the plurality of battery cells protruding from the cell casing are at least partially embedded in a potting compound, wherein the potting compound can be temperature controlled by a temperature control element.

[0008] Document DE 10 2011 079 394 A1 discloses an energy storage module.

[0009] The object of the present invention is to charge the batteries of a battery module particularly quickly. Disclosure of the invention

[0010] The above problem is solved according to the invention in accordance with independent claim 1.

[0011] The invention relates to a fast-charging method for the battery module of an electric vehicle. The fast-charging method comprises cooling a cooling device to a temperature below 0 °C. The cooling device can be located in the electric vehicle near the battery module or, alternatively, in a stationary charging station. In an optional step, an electrical connection is established between the battery module and the stationary charging station. Subsequently, the battery module or the battery cells are electrically charged, and the cooling device is connected to a heat sink or to at least one battery cell of the battery module.Preferably, the thermally conductive contact between the cooling device and the heat busbar is established before charging and / or by means of an additional thermally conductive switch, which can establish or break the thermally conductive contact between the cooling device and the heat busbar via a control signal. Due to the low temperature of the cooling device, a large temperature difference results between the battery cell and the cooling device, thus increasing the heat flow between the battery cell and the cooling device. This allows for higher charging power or a shorter charging time. After charging, the thermally conductive contact between the heat busbar and the cooling device is broken in a further optional step.

[0012] The battery module comprises at least one battery cell. The battery module includes a first contact element that makes electrical and thermal contact with a first terminal of the battery cell, and a second contact element that makes electrical and thermal contact with a second terminal of the battery cell. Preferably, the first terminal is located on an upper outer surface of the battery cell and the second terminal on a lower outer surface of the battery cell. At least one electrically insulating insulating area makes thermal contact with the first contact element and / or the second contact element. The at least one insulating area is made thermally contacted on the side opposite the first contact element and / or the second contact element by a heat sink. Thus, the heat sink indirectly makes thermal contact with the battery cell via the at least one insulating area, the first contact element, and / or the second contact element.This allows the battery module, via the heat sink, to supply or dissipate heat to the battery cell via the first and second terminals. Such heat conduction to or from the battery cell is efficient because the first and / or second contact elements are metallic, and the insulation layer can be thin, resulting in low thermal resistance between the heat sink and the battery cell. Heat generated, for example, during charging due to ohmic losses, can be dissipated from the battery module via the heat sink. Furthermore, heat can be supplied to or dissipated more homogeneously than in the prior art via the two terminals of the battery cell, resulting in lower temperature gradients within the battery cell, particularly when the two terminals are located on opposite outer surfaces of the battery cell.This reduces mechanical stresses in the battery cell. A particular advantage is that no additional cooling device needs to be located in the immediate vicinity of the battery cells, for example between them, because the first and / or second contact element is used to dissipate or conduct heat; that is, the electrical contacts also perform a thermal conductivity function.

[0013] In a preferred embodiment, a first insulating zone is arranged between the first contact element and the heat busbar, and a second insulating zone is arranged between the second contact element and the heat busbar. The first and second insulating zones are spaced apart from each other. By designing a separate insulating zone for each contact element, the distance between the first and second contact elements can be reduced, thereby increasing the contact area between the first and second contact elements and the heat busbar.

[0014] In one embodiment, the battery module comprises a holder for the battery cell and at least one external contact element. The external contact element projects into the holder, meaning it makes thermally conductive contact with the holder. The external contact element also makes thermally conductive contact with the first or second contact element. The holder, in turn, makes thermally conductive contact with the battery cell, particularly with a large cross-sectional area of ​​the thermally conductive contact. This embodiment allows heat to be indirectly supplied to or dissipated from the battery cell via the external contact element or the holder, either through the outer surface of the battery cell. The cross-sectional area of ​​the thermally conductive contact of the external contact elements is relatively large compared to the metallic heat sinks of the battery cell, thus reducing the thermal resistance between the first contact element and the battery cell.the second contact element and the battery cell is reduced.

[0015] In a further development, the external contact element makes direct thermal contact with an outer surface of the battery cell. This reduces the thermal resistance between the first or second contact element and the battery cell.

[0016] Preferably, the heat busbar also makes thermally conductive contact with an outer casing of the battery module. This allows the heat generated, for example, during the charging or discharging of the at least one battery cell, to be dissipated to the outer casing of the battery module. Additional heat sinks, in particular cooling fins, or a heat storage device, in particular a latent heat storage device, can be arranged on the outer casing. The outer casing can therefore represent a large heat sink. The outer casing can also be actively cooled, for example, by the airflow from an electric vehicle via forced convection.

[0017] The battery module particularly preferably includes a thermal break element. The thermal break element comprises at least one insulation area and the heat sink. Furthermore, the thermal break element includes at least one housing, at least one first plug-in contact for thermally conductive connection with the first contact element, and at least one second plug-in contact for thermally conductive connection with the second contact element. The thermal break element advantageously facilitates the simple manufacture of the battery module; for example, it simplifies assembly and disassembly.

[0018] In an optional extension, the thermal break element on the heat busbar has at least one third plug contact for thermally conductive contacting the heat busbar with an external heat conductor and / or with another battery module. This allows the battery module to be advantageously connected via a simple plug connection to a cooling or heating device outside the battery module or to other battery modules in a thermal management system.

[0019] The present invention is explained below with reference to preferred embodiments and accompanying drawings. Fig. 1: Battery module Fig. 2: Battery module with multi-part insulation area Fig. 3: Battery module with additional external contact elements Fig. 4: Battery module, with the heat busbar contacting the outer casing Fig. 5: Battery module with thermal break element Fig. 6: Flowchart of the fast charging process Examples of implementation

[0020] In Fig. Figure 1 shows a battery module 100. The battery module 100 comprises a battery cell 103, which is held in a battery cell holder 110. The battery cell 103 is electrically and thermally contacted by a first contact element 101 at an upper, first electrical pole 104 and by a second contact element 102 at a lower, second electrical pole 105. In this embodiment, the first contact element 101 and the second contact element 102 are each bent over on a side surface 120 of the holder 110. In the bent areas 130, the first contact element 101 and the second contact element 102 contact an insulating area 106.The insulating area 106 is thermally conductive and electrically insulating. For example, the insulating area 106 comprises a polymer coating, a thermally conductive gel, and / or a thermally conductive pad, wherein the thermally conductive pad may, in particular, comprise a silicone rubber, a mica and / or a ceramic disc, and / or a plastic film. The insulating area 106 is arranged between the first contact element 101 or the second contact element 102 and a heat busbar 107. That is, the battery module 100 comprises an electrically insulating insulating area 106, which thermally contacts the first contact element 101 and the second contact element 102 as well as the heat busbar 107. The heat busbar 107 is arranged on the side of the insulating area 106 opposite the first contact element 101 and the second contact element 102. The heat busbar 107 preferably comprises a metal.The heat busbar 107 thus indirectly makes thermal contact with the battery cell 103 at the first terminal 104 from above and at the second terminal 105 from below via the insulation area 106 and via the first contact element 101 and the second contact element 102. The battery module 100 is made of... Fig. 1 is therefore equipped by means of the heat collection rail 107 to supply or remove heat from the battery cell 103 from above and below. This allows the battery cell 103 to be heated or cooled evenly from above and below.

[0021] In Fig. 2 is opposite the battery module 100. Fig. Figure 1 shows a different configuration of the insulation area 106. Fig. 2. A separate first insulation area 106a is provided for the first contact element 101 and a separate second insulation area 106b for the second contact element 102. By providing separate insulation areas 106a and 106b for each contact element, the distance 150 between the first contact element 101 and the second contact element 102 can be reduced, thereby increasing the contact area between the first contact element 101 or the second contact element 102 and the heat busbar 107.

[0022] In Fig. 3 is the battery module 100 from Fig. 2 shown, where the battery module 100 in Fig. 3 additionally comprises a first external contact element 301 formed on the first contact element 101 and a second external contact element 302 formed on the second contact element 102. The first external contact element 301 and the second external contact element 302 each make thermally conductive contact with at least the holder 110 for battery cells 103, the holder 110 in turn making thermally conductive contact with the battery cell 103. In the exemplary embodiment from Fig. The first external contact element 301 and the second external contact element 302 each directly contact an outer surface 303 of the battery cell 103. Thus, the heat busbar 107 indirectly contacts the battery cell 103 from above and below, as well as the outer surface 303, via the first insulation area 106a and the second insulation area 106b, respectively. The first contact element 101 contacts the first external contact element 301, and the second contact element 102 contacts the second external contact element 102, thus thermally conducting the heat busbar 107. This results in a low overall thermal resistance between the battery cell 103 and the heat busbar 107 and homogeneous heat conduction. This means that a large amount of heat can be quickly and homogeneously supplied to or removed from the battery cell 103. A battery cell 103 with such thermally conductive contact can therefore be heated or cooled particularly homogeneously.This allows for increased performance and a longer lifespan of battery cell 103. For example, the maximum current during charging or discharging of battery cell 103 can be increased, resulting in reduced charging and discharging times for battery cell 103.

[0023] In Fig. The battery module 4 comprises 100 Fig. 1. Additionally, an outer housing 401. The holder 110, the battery cell 103, the first contact element 101 and the second contact element 102, the insulation area 106, and the heat busbar 107 are arranged inside the outer housing 401. In this embodiment, the heat busbar 107 makes thermally conductive contact with the outer housing 401. The outer housing 401 comprises, for example, a metal, in particular aluminum. Accordingly, heat generated by discharge or charging processes in the battery cell 103 can be dissipated to the outer housing 401 via the heat busbar 107. Alternatively, the thermally conductive contact between the outer housing 401 and the heat busbar 107 can be switched by a switch, i.e., the outer housing 401 is only thermally connected to the heat busbar 107 when the thermally conductive switch is closed.The outer casing 401 is designed to absorb a large amount of heat and / or dissipate it to the environment, for example, by means of free convection at optional cooling fins or forced convection (not shown). The outer casing 401 preferably acts as a large heat sink. A heat storage device can additionally be arranged in the battery module 100, which is directly thermally connected to the heat busbar 107 and / or to the outer casing 401. The heat storage device can preferably be a latent heat storage device with a phase-change material. Alternatively, the heat busbar 107 can be directly connected to the heat storage device; optionally, the thermally conductive contact between the heat busbar 107 and the heat storage device can be switchable.

[0024] Preferably, the cross-sections of the first contact element 101, the second contact element 102, and the heat-harvesting rail 107, as well as the contact area of ​​the insulating region 106, are sufficiently large, and their thermal conductivities are sufficiently good to ensure that a sufficient amount of heat can be dissipated through the heat-harvesting rail 107 during charging or discharging of the battery module 100, in particular to keep the temperature of the battery module 200 below 60 °C during charging. A temperature of 60 °C or less results in efficient chemical processes and / or avoids chemical side reactions in the battery cell 103.

[0025] In Fig. The battery module 100 comprises a thermal break element 500. The thermal break element 500 includes a housing 510, a first plug contact 501, a second plug contact 502, the first insulation area 106a, the second insulation area 106b, the heat busbar 107, and a third plug contact 504. The first plug contact 501 is configured to be thermally connected to the first contact element 101, and the second plug contact 502 is configured to be thermally connected to the second contact element 102. The third plug contact 504 is configured to be thermally connected to an external heat conductor 505 or another battery module 100. The external heat conductor 505 is thermally contacted at its other end, for example, with an active or passive cooling device, a heat storage device, and / or a heating device (not shown).Alternatively, the thermal break element 500 can have at least two third plug contacts 504. The battery module 100 made of . Fig. 5 is configured to supply or remove heat to the battery cell 103 by means of at least one external heat conductor 505. By means of such a configuration of the battery module 100, an efficient, central cooling and / or heating device can be provided in an electric vehicle, wherein the central cooling and / or heating device thermally contacts and regulates the temperature, i.e., cools or heats, at least one battery module 100.

[0026] For fast charging of the battery module 100, a cooling device is in thermally conductive contact with the heat busbar 107, whereby the cooling device generates the lowest possible temperature. This increases the temperature difference between the at least one battery cell 103 and the cooling device; that is, the lower the temperature, the greater the heat flow or the amount of heat that can be dissipated per unit of time. In particular, the temperature generated by the cooling device is less than 0 °C. This allows the amount of heat that can be dissipated, or the charging or discharging power, to be increased. The cooling device can be operated, for example, by a high current during fast charging and / or in an emergency, such as a short circuit in a battery cell 103, by discharging an adjacent battery module 100.

[0027] In Fig.Figure 6 shows a flowchart of the fast-charging process for the battery module 100. The fast-charging process includes cooling 610 by a cooling device to a temperature below 0 °C. In an optional step 620, an electrical contact is then established between the battery module and a power source. Preferably, in the optional step 620, the battery module 100 is electrically connected to a charging station, for example, by connecting an electrical charging plug to a charging socket or by bringing an induction coil near an alternating electromagnetic field. Subsequently, the battery module or the at least one battery cell 103 is charged 630. In a further step 640, the cooling device is cooled with a heat sink or...The battery cell 103 of the battery module is thermally contacted, in particular by means of a switch that can establish or break a thermally conductive contact between the heat busbar 107 and the battery cell 103. The switch can, for example, be arranged between the heat busbar 107 and a third plug contact 504. Due to the low temperature of the cooling device, a large temperature difference results between the battery cell 103 and the cooling device, so that the heat flow between the battery cell 103 and the battery module 100 is increased during charging 630. Thus, higher charging power or a shorter charging time can be achieved during charging 630. The cooling device is preferably arranged in the electric vehicle near the battery module or alternatively in a stationary charging station. After charging 630 of the at least one battery cell 103 or the battery module 100, the cooling device is cooled by the heat busbar 107.In a further step 650 of the battery module 100, the thermally conductive contact between the cooling device and the heat busbar 107 or the battery cell 103 is separated or interrupted, in particular by means of the switch.

[0028] In one embodiment of the fast charging process, the cooling device 610 is cooled to a temperature below -20 °C. This increases the temperature difference between the battery cell and the cooling device, which also increases the heat flow.

[0029] In a further embodiment of the fast charging method, the cooling device is operated by the charging current, so that no energy from the battery module is required to operate the cooling device.

[0030] Preferably, the cooling device has a large heat capacity, so that its temperature rises little or only slowly during charging. For this purpose, the cooling device includes a large heat storage unit, for example, a container with water and antifreeze or a container with a phase-change material. The heat storage unit preferably also has a temperature below 0 °C during charging. This ensures that the heat flow during charging of the battery module remains approximately constant or is only slightly reduced.

Claims

[1] Fast charging method for a battery module (100) comprising a heat busbar (107) which thermally contacts at least one battery cell (103) of the battery module (100), comprising the following steps a. Cooling (610) of a cooling device to a temperature below 0 °C, b. Charging (630) of the battery module (100), and c. thermally conductive contact (640) of the cooling device with the heat busbar (107) of the battery module (100), wherein the battery module (100) at least a. a battery cell (103), b. a first contact element (101) which electrically and thermally contacts a first pole (104) of the battery cell (103), c. a second contact element (102) which electrically and thermally contacts a second pole (105) of the battery cell (103), d. at least one electrically insulating insulation area (106, 106a, 106b), wherein the insulation area (106, 106a, 106b) thermally contacts the first contact element (101) and / or the second contact element (102), and e. the heat busbar (107) having a heat busbar, wherein the heat busbar (107) indirectly thermally contacts the first contact element (101) and the second contact element (102) via the at least one insulation area (106, 106a, 106b), whereby the battery module (100) is equipped by means of the heat busbar (107) to supply or remove heat to the battery cell (103) via the first pole (104) and via the second pole (105). [2] Fast charging method (100) according to claim 1, characterized by, that a first insulation area (106a) is arranged between the first contact element (101) and the heat busbar (107) and a second insulation area (106b) is arranged between the second contact element (102) and the heat busbar (107). [3] Fast charging method according to one of claims 1 or 2, characterized by , that the battery module (100) comprises a holder (110) for the battery cell (103) and at least one external contact element (301, 302), wherein the external contact element (301, 302) projects into the holder (110) and thermally contacts the first contact element (101) or the second contact element (102). [4] Fast charging method according to claim 3, characterized by , that the external contact element (301, 302) directly contacts an outer surface (303) of the battery cell (103) in the holder (304) in a thermally conductive manner. [5] Fast charging method according to any one of the preceding claims, characterized by, that the heat busbar (107) thermally contacts an outer casing (401) of the battery module (100). [6] Fast charging method according to any one of claims 1 to 4, characterized by , that the battery module (100) comprises a thermal break element (500), wherein the thermal break element (500) has at least one insulation area (106, 106a, 106b), the heat busbar (107) and additionally at least the following components a. a case (510), b. at least one first plug contact (501) for thermally conductive connection with the first contact element (101), and c. at least one second plug contact (502) for thermally conductive connection with the second contact element (102). [7] Fast charging method according to claim 6, characterized by, that the heat separation element (500) on the heat busbar (107) includes a third plug contact (504) for thermally conductive contacting of the heat busbar (107) with an external heat conductor (505), with a cooling device and / or with another battery module (100).

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