Two-component potting for rechargeable batteries

Abstract

A rechargeable battery, in particular as a removable energy supply for a power tool, contains at least one energy storage element having a contact means, a control device, a potting chamber, and a rechargeable battery interface for selectively connecting the rechargeable battery to a power tool or a charging device. At least a first potting material and a second potting material are contained in the potting chamber, where the first potting material has a higher thermal conductivity than the second potting material and the second potting material has a lower electrical conductivity than the first potting material, and where the first potting material has a higher thermal conductivity than the second potting material. The second potting material covers at least a portion of the contact means of the at least one energy storage element.

Description

Technical Field

[0001] The present invention relates to a rechargeable battery, in particular a rechargeable battery as a removable energy supply for a power tool, the rechargeable battery comprising at least one energy storage element with a contact device, a control device, a potting chamber and a rechargeable battery interface for selectively connecting the rechargeable battery to a power tool or a charging device. Background Art

[0002] Rechargeable batteries are well known in the prior art as energy supplies for power tools. These rechargeable batteries usually include a plurality of energy storage cells (also called rechargeable battery cells) that are used and designed to receive, store and deliver electrical energy. Receiving electrical energy into the energy storage cells may also be referred to as charging (or loading). The delivery of electrical energy from the energy storage cells may also be referred to as discharging.

[0003] In order to load or charge with electrical energy, rechargeable batteries are usually connected to a charging device (also called a charger). The charging device conducts the electrical energy according to a predetermined charging profile (also called a charging mode) which has defined parameters for the actual charging process at the individual energy storage cells of the rechargeable battery.

[0004] In particular, when rechargeable batteries are used intensively (ie with high and rapid supply of electrical energy), the energy storage elements of the rechargeable batteries heat up to critical values. In other words: Here, the rechargeable batteries may be heated undesirably to such an extent that permanent damage cannot even be ruled out.

[0005] However, conventional commercially available systems for cooling rechargeable batteries are often complex and / or expensive. Summary of the invention

[0006] The object of the present invention is to solve the above-mentioned problems.

[0007] This object is likewise achieved by the subject matter of claim 1. Further advantageous embodiments of the invention are described in the corresponding dependent claims.

[0008] This object is achieved in particular by a rechargeable battery, in particular as a rechargeable battery for a power tool as a removable energy supply, which rechargeable battery contains at least one energy storage element with a contact device, a control device, a sealing chamber and a rechargeable battery interface for selectively connecting the rechargeable battery to a power tool or a charging device.

[0009] According to the present invention, it is proposed that at least a first potting material and a second potting material are contained in a potting chamber, wherein the first potting material has a higher thermal conductivity than the second potting material, and the second potting material has a lower electrical conductivity than the first potting material, and wherein the second potting material covers at least a portion of the contact device of the at least one energy storage element.

[0010] According to an advantageous exemplary embodiment, it is possible that the first potting material at least partially contains a thermally conductive epoxy adhesive.

[0011] The first potting material may also at least partially contain a thermosetting polymer.The thermal conductivity may be produced by adding at least one thermally and / or electrically conductive filler.

[0012] According to a further advantageous exemplary embodiment, it is possible that the second potting material at least partially contains non-conductive silicone, wherein the non-conductive silicone takes the form of 1K or 2K silicone.

[0013] According to an advantageous exemplary embodiment, it is possible that the first potting material fills at least 50% of the volume of the potting chamber.

[0014] According to a further advantageous exemplary embodiment, it is possible that the first potting material fills less than 50% of the volume of the potting chamber.

[0015] According to an advantageous exemplary embodiment, it is possible that the first potting material has a thermal conductivity of 0.75 to 1 W / (m*K). The first potting material may also have a thermal conductivity of 3 to 10 W / (m*K).

[0016] According to a further advantageous exemplary embodiment, it is possible that the first potting material is polyurethane-based and preferably an elastomer.

[0017] According to an advantageous exemplary embodiment, it is possible that the first potting material has a UL94 flammability rating of V0.

[0018] According to a further advantageous exemplary embodiment, it is possible that the at least one energy storage element is based on lithium-ion or Li-polymer technology.

[0019] According to an advantageous exemplary embodiment, it is possible that the no-load voltage is limited to 60 Volts. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Further advantages can be found in the following description of the drawings. Particularly preferred exemplary embodiments of the present invention are shown in the drawings. The drawings, the description and the claims include many combined features. Those skilled in the art will also conveniently consider these features individually and combine these features to form other reasonable combinations.

[0021] In the accompanying drawings, the same and similar components are denoted by the same reference numerals.

[0022] In the attached picture:

[0023] Figure 1 shows a side view of a power tool and a rechargeable battery according to the present invention;

[0024] Figure 2 shows a cross-sectional side view of a rechargeable battery according to the present invention;

[0025] Figure 3 shows a rechargeable battery along Figure 2 A cross-sectional view of the cutting plane AA; and

[0026] Figure 4 shows a rechargeable battery along Figure 2 Cross-sectional view of cutting plane BB. DETAILED DESCRIPTION

[0027] Figure 1 A power tool 1 and a rechargeable battery 2 according to an exemplary embodiment are shown. The rechargeable battery 2 is removably connected to the power tool 2 so as to supply the power tool 2 with electrical energy.

[0028] In the illustrated embodiment, the power tool 1 is configured as a power drill. Alternatively, the power tool 1 may also be configured as a screwdriver, a hammer drill, a saw, a grinder, and the like.

[0029] like Figure 1 The indicated power tool 1 configured as a power drill substantially contains a power tool housing 3 having a tool accessory 4 and a handle 5 .

[0030] The tool accessory 4 is used to receive and hold a tool 6 .

[0031] In the present exemplary embodiment, the tool 6 is a drill bit. Alternatively, the tool 6 may also be configured as a screwdriver bit.

[0032] In particular, a drive 7 , a transmission 8 , an output shaft 9 and a control unit 10 are arranged inside the power tool housing 3 .

[0033] The driver 7 is configured as, for example, a brushless electric motor and is used to generate torque.

[0034] The control unit 10 controls the functions and behavior of the power tool 1 , in particular the drive 7 , ie the rotation direction and speed of the drive 7 , in closed-loop and open-loop manner.

[0035] The handle 5 in turn comprises an activation switch 11 , an upper end 5a and a lower end 5b. The activation switch 5 is connected to a control unit 10 such that actuation of the activation switch 11 results in activation of the driver 7 or the power tool 1 .

[0036] Also like Figure 1 As shown, the drive 7, the transmission 8, the output shaft 9 and the tool accessory 4 are arranged relative to each other so that the torque generated by the drive 7 can be transmitted to the tool accessory 4 via the transmission 8 and the output shaft 9. The torque generated by the drive is finally transmitted to the tool 6 through the tool accessory 4.

[0037] Furthermore, the power tool housing 3 has an upper side 3 a , a lower side 3 b , a front end 3 c , and a rear end 3 d .

[0038] Tool accessories are positioned at the front end. The upper end 5a of the handle 5 is fastened to the underside 3b of the power tool housing 3 near the rear end 3d. The power tool interface 12 is positioned at the lower end 5b of the handle 5. The power tool interface 12 is used to removably connect the power tool 1 to the rechargeable battery 2.

[0039] According to an alternative exemplary embodiment (not shown in the figures), the power tool 1 can also be configured such that it is connected to more than one rechargeable battery 2 as energy source.

[0040] The rechargeable battery 2 described in the exemplary embodiment can be used in particular as an energy storage device or electrical energy source for the power tool 1. The rechargeable battery 2 here essentially contains a rechargeable battery housing 13, a plurality of energy storage cells 14, a rechargeable battery interface 15, a potting chamber 16 and a control device 17.

[0041] The energy storage cell 14 may also be referred to as a rechargeable cell.

[0042] The rechargeable battery interface 15 is used to electrically or electronically connect the rechargeable battery 2 to the power tool 1 by means of the power tool interface 12. For this purpose, the rechargeable battery interface 15 includes a positive contact P, a negative contact M and a communication contact K. The positive contact P and the negative contact M are used to transmit electrical energy from the energy storage cell 14 of the rechargeable battery 2 to the consumer device (especially the drive 7) of the power tool 1.

[0043] The communication contacts K in turn serve for communication between the control device 17 of the rechargeable battery 2 and the control unit 10 of the power tool 1. For the communication between the rechargeable battery 2 and the power tool 1, data and information are exchanged in the form of signals.

[0044] The energy storage cell 14 is used to receive, store and retransmit electrical energy. As indicated in the figure, the energy storage cell 14 is cylindrical and is configured based on lithium-ion technology. As indicated in the figure, each energy storage cell 14 contains a contact device 18 for transmitting electrical energy at one end. As also shown in the figure, each contact device 18 is connected to the control device 17 via a corresponding line 19.

[0045] Alternatively, the energy storage cell 14 may also be based on another suitable technology.

[0046] The cylindrical shape of the energy storage cell 14 is likewise optional, so that any other suitable shape or geometry can also be selected. Thus, it is also possible in particular for the energy storage cell 14 to be configured as a pouch cell.

[0047] In addition, it is also possible that the rechargeable battery 2 contains both cylindrical energy storage cells and pouch-type cells. In particular, it is possible that the rechargeable battery 2 contains a single cylindrical energy storage cell and a single pouch-type cell.

[0048] The control device 17 controls different functions of the rechargeable battery 2 in a closed-loop and open-loop manner. In addition, the control device 17 is connected to the energy storage cell 14 and the rechargeable battery interface 15 via corresponding lines 20, so that electrical energy can be transferred from the energy storage cell 14 to the rechargeable battery interface 15 via the control device 17.

[0049] In order to removably mechanically couple the rechargeable battery 2 to the power tool 1, the system consisting of the power tool 1 and the rechargeable battery 2 contains a track device 21. As indicated in the figure, the track device 21 is positioned between the rechargeable battery interface 15 and the power tool interface 12, so that the rechargeable battery 2 can slide along the track device 21 and slide onto the power tool 1 in the direction of the arrow C and be removed (slided) from the power tool 1 again in the direction of the arrow D. If the rechargeable battery 2 is coupled to the power tool 1 by means of the track device 21, the positive contact P, the negative contact M and the communication contact K of the rechargeable battery 2 are in contact with the corresponding positive contact P and the negative contact M and the communication contact K of the power tool 1. Electrical energy and electrical signals can then be transmitted from the rechargeable battery 2 to the power tool 1.

[0050] A locking device (not shown in the figures) is used to removably connect the rechargeable battery 2 to the power tool 1 .

[0051] The potting chamber 16 is basically configured as a tray having a cavity 22 . The energy storage cells 14 are positioned in the cavity 22 .

[0052] The potting chamber 16 is also configured such that a liquid potting material VM can be introduced and retained.

[0053] The first potting material VM1 and the second potting material VM2 are poured into the rechargeable battery 2 according to the first exemplary embodiment around the plurality of energy storage elements 14 .

[0054] In this case, the first sealing material VM1 has a higher thermal conductivity than the second sealing material VM2 .

[0055] According to the first exemplary embodiment, the thermal conductivity of the first potting material VM1 is 0.8 W / (m*K).

[0056] In contrast, the thermal conductivity of the second encapsulation material VM2 is 0.2 W / (m*K).

[0057] Alternatively, the thermal conductivity of the first encapsulation material VM1 may be 0.75 to 1 W / (m*K). Here, the value of the thermal conductivity of the second encapsulation material VM2 is substantially half the value of the thermal conductivity of the first encapsulation material VM1. Alternatively, the value of the thermal conductivity of the second encapsulation material VM2 may be only one quarter (=1 / 4) of the value of the thermal conductivity of the first encapsulation material VM1.

[0058] In addition, the second encapsulation material VM2 has a lower electrical conductivity (specific resistance, i.e., at least 10 10 Ωcm). In this case, the value of the electrical conductivity of the first sealing material VM1 is at least twice the value of the electrical conductivity of the second sealing material VM2.

[0059] If especially in Figure 2 and Figure 3 As indicated in , the potting chamber 16 is not filled with the first potting material VM1 and the second potting material VM2 in the same volume ratio. According to the first exemplary embodiment, the first potting compound VM1 fills about 70% of the volume of the potting chamber 16. In contrast, the second potting material VM2 fills about 20% of the volume of the potting chamber 16. The remaining 10% of the volume of the potting chamber 16 is filled with air. The first potting material VM1 and the second potting material VM2 are positioned in the potting chamber 16 so that the second potting material VM2 encapsulates the upper part of the energy storage cell 14 with the corresponding contact device 18. Therefore, a part of the contact device 18 remains free of the second potting material VM2, so that in each case, the line 20 leads from the free (uncovered) end of the contact device 18 to the control device 17.

[0060] Alternatively, the first potting material may fill 70% of the volume of the potting chamber 16 and the second potting material VM2 may fill 30% of the volume of the potting chamber 16 , so that there is no longer any volume of the potting chamber 16 filled with air.

[0061] The relatively high proportion of the second potting material VM2 ensures an almost optimal heat dissipation from the energy storage cells 14 .

[0062] List of Reference Numerals

[0063] 1. Power Tools

[0064] 2 rechargeable batteries

[0065] 3Power tool housing

[0066] 3a Upper side of the power tool housing

[0067] 3b Underside of the power tool housing

[0068] 3c Front end of the power tool housing

[0069] 3d Rear end of the power tool housing

[0070] 4Tool Accessories

[0071] 5 handles

[0072] 5a Upper end of the handle

[0073] 5b Lower end of handle

[0074] 6 Tools

[0075] 7. Drive

[0076] 8 Transmission

[0077] 9 Output shaft

[0078] 10 Control unit

[0079] 11 Actuation switch

[0080] 12 Power tool interface

[0081] 13 Rechargeable battery housing

[0082] 14 Energy storage cells

[0083] 15 Rechargeable battery port

[0084] 16 Potting Room

[0085] 17 Control Device

[0086] 18 Contact device

[0087] Lines 19 and 20

[0088] 21 Track equipment

[0089] 22 Cavity

[0090] P positive contact

[0091] M Negative contact

[0092] K Communication contact

Claims

1. A rechargeable battery (2), in particular as a removable energy supply for a power tool (1), comprising at least one energy storage element (14) with a contact device (18), a control device (17), a potting chamber (16) and a rechargeable battery interface (15) for selectively connecting the rechargeable battery (2) to a power tool (1) or a charging device, It is characterized in that At least a first and a second potting material (VM1, VM2) are contained in the potting chamber (16), wherein the first potting material (VM1) has a higher thermal conductivity than the second potting material (VM2), and the second potting material (VM2) has a lower electrical conductivity than the first potting material (VM1), and wherein the second potting material (VM2) covers at least a portion of a contact device (18) of the at least one energy storage element (14).

2. The rechargeable battery (2) as claimed in claim 1, It is characterized in that The first potting material (VM1) at least partially contains a thermally conductive epoxy resin adhesive.

3. The rechargeable battery (2) according to claim 1 or 2, It is characterized in that The second encapsulation material (VM2) at least partially contains non-conductive silicone, wherein the non-conductive silicone takes the form of 1K or 2K silicone.

4. The rechargeable battery (2) according to at least one of claims 1 to 3, It is characterized in that The first potting material (VM1) fills at least 50% of the volume of the potting chamber (16).

5. The rechargeable battery (2) according to at least one of claims 1 to 3, It is characterized in that The first potting material (VM1) fills less than 50% of the volume of the potting chamber (16).

6. The rechargeable battery (2) according to at least one of claims 1 to 3, It is characterized in that The first encapsulation material (VM1) has a thermal conductivity of 0.75 to 1 W / (m*K).

7. The rechargeable battery (2) according to at least one of claims 1 to 6, It is characterized in that The first potting material (VM1) is polyurethane-based and is preferably an elastomer.

8. The rechargeable battery (2) according to at least one of claims 1 to 7, It is characterized in that The first potting material (VM1) has a UL94 flammability rating of V0.

9. The rechargeable battery (2) according to at least one of claims 1 to 8, It is characterized in that The at least one energy storage element (14) is based on lithium-ion or Li-polymer technology.

10. The rechargeable battery (2) according to at least one of claims 1 to 9, It is characterized in that No-load voltage is limited to 60 volts.

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