Interchangeable rechargeable battery pack for a consumer

Abstract

The invention relates to an interchangeable rechargeable battery pack (1) for a consumer, in particular for a power tool, comprising at least two rechargeable cells (2), at least one cell connector (4), and a first contact element (11) and a second contact element (12) for electrically connecting the interchangeable rechargeable battery pack (1), wherein each rechargeable cell (2) is electrically conductively connected to the at least one cell connector (4) by means of a connection (5), and wherein the rechargeable cells (2) and the at least one cell connector (4) and each connection (5) are configured such that a total AC internal resistance of the interchangeable rechargeable battery pack (1) between the first contact element (11) and the second contact element (12) is at most 40 milliohms.

Description

[0001] Description

[0002] title

[0003] Removable battery pack for one consumer

[0004] State of the art

[0005] The present invention relates to a replaceable battery pack for a consumer, as well as a consumer, in particular a power tool.

[0006] Interchangeable battery packs for consumers, such as power tools, are well known. These packs contain multiple battery cells for storing electrical energy to power the consumer. The efficiency and operational reliability of such interchangeable battery packs typically depend on a variety of factors. A particularly important factor is often the electrical transmission path, originating from the electrical energy chemically stored within the battery cells. Due to the large number of components of the interchangeable battery pack, which are often interconnected, and additional requirements regarding space and weight, multiple loss factors often result, which impair the efficiency of the battery pack.

[0007] Disclosure of the invention

[0008] The interchangeable battery pack according to the invention with the features of claim 1 is characterized by particularly high performance. In particular, higher power levels, preferably a greater electrical current, can be drawn from the interchangeable battery pack. Furthermore, heating of the interchangeable battery pack during operation can advantageously be reduced, thereby increasing, in particular, the longevity, operational reliability, and efficiency of the interchangeable battery pack. This is achieved according to the invention by an interchangeable battery pack for a consumer, in particular for a power tool, comprising at least two battery cells, at least one cell connector, and a first contact element and a second contact element. The two contact elements are designed for the electrical connection of the interchangeable battery pack.This means that the electrical energy can be supplied to other components of the consumer, such as an electric motor, at the two contact elements. Preferably, different electrical potentials are present at the two contact elements. Each battery cell of the removable battery pack is electrically connected to the at least one cell connector by means of a connection. The battery cells, the at least one cell connector, and each connection are designed such that the total AC internal resistance of the removable battery pack between the first contact element and the second contact element is a maximum of 40 milliohms.

[0009] The AC internal resistance is defined as the alternating current internal resistance. This AC internal resistance is preferably determined using a standardized measurement method, preferably according to DIN EN IEC 61960.

[0010] Alternatively or additionally, the battery cells and the at least one cell connector and each connection of the removable battery pack can preferably be designed such that a total DC internal resistance is a maximum of 12 milliohms, preferably a maximum of 9 milliohms, in particular a maximum of 7 milliohms. The DC internal resistance can be considered a direct current internal resistance. Such a DC internal resistance is preferably determined according to a standardized method, such as DIN EN IEC 61960.

[0011] In other words, a removable battery pack is provided in which preferably all elements inside the removable battery pack involved in providing the electrical current are designed and preferably coordinated with one another in such a way that the total AC internal resistance is as low as possible, specifically a maximum of 40 milliohms. This can preferably be achieved in a variety of ways, for example by providing battery cells with low internal resistance, by providing cell connectors with the lowest possible electrical resistance, and by connections that have optimal efficiency in power transmission. The removable battery pack according to the invention offers the advantage that an electrical energy storage device with particularly high performance can be provided for consumers, such as power tools.The particularly low AC internal resistance enables a particularly high power output from the removable battery pack. This allows for higher power output, especially through higher currents. At the same time, the heating of the removable battery pack, especially the battery cells, during operation can be reduced. This not only increases the service life and operational reliability of the removable battery pack, but also further increases the efficiency of the battery cells.

[0012] The subclaims contain preferred developments of the invention.

[0013] Preferably, the battery cells and the at least one cell connector and each connection of the interchangeable battery pack are designed such that the total AC internal resistance of the interchangeable battery pack is a maximum of 30 milliohms, in particular a maximum of 21 milliohms. This allows for the provision of a particularly powerful and efficient interchangeable battery pack.

[0014] Particularly preferably, a plurality of battery cells are electrically connected to one another in series by means of the at least one cell connector. Alternatively or additionally, a plurality of battery cells are electrically connected to one another in parallel by means of the at least one cell connector. This allows for a flexible adjustment of the total electrical capacity that can be provided by the interchangeable battery pack and / or the total electrical current that can be provided by the interchangeable battery pack.

[0015] Preferably, five battery cells are electrically connected to one another in series. In particular, the battery cells are electrically connected exclusively in series. This means that the battery cells are preferably interconnected in a single layer. For example, such a configuration can also be referred to as a 5s1p configuration of the replaceable battery pack. For example, when using battery cells which have a cell voltage of 3.6 V per battery cell, a replaceable battery pack with a total voltage of 18 V can be provided. The battery cells and the at least one cell connector and all connections of the replaceable battery pack are preferably designed such that the total AC internal resistance is a maximum of 21 milliohms, preferably a maximum of 16 milliohms, in particular a maximum of 11 milliohms.

[0016] Preferably, five battery cells are electrically connected in series. In addition, two battery cells are electrically connected in parallel. For example, such a configuration can also be referred to as a 5s2p configuration of the interchangeable battery pack. For example, when using battery cells that have a cell voltage of 3.6 V per battery cell, a interchangeable battery pack with a total voltage of 18 V can be provided. Preferably, the battery cells and the at least one cell connector and all connections of the interchangeable battery pack are designed such that the total AC internal resistance is a maximum of 12 milliohms, preferably a maximum of 9 milliohms, in particular a maximum of 6 milliohms.

[0017] More preferably, five battery cells are connected in series. Additionally, three battery cells are connected in parallel. For example, such a configuration can also be referred to as a 5s3p configuration of the interchangeable battery pack. Preferably, the battery cells and the at least one cell connector and all connections of the interchangeable battery pack are designed such that the total AC internal resistance is a maximum of 7 milliohms, preferably a maximum of 6 milliohms, in particular a maximum of 4 milliohms. This allows for the provision of a particularly powerful interchangeable battery pack.

[0018] The battery cells are particularly preferably designed as lithium-ion battery cells. A particularly advantageous configuration of the battery cells is a multi-tab configuration, i.e., in particular, with a plurality of tabs that form the electrical pole of the battery cell or are connected to it. Such a multi-tab configuration of a lithium-ion battery cell offers the advantage of a particularly low internal resistance. Such battery cells with a maximum AC internal resistance of 8 milliohms, preferably e milliohms, in particular 4 milliohms, per battery cell are particularly advantageous. This makes it possible to provide a replaceable battery pack with a particularly low overall AC internal resistance and thus particularly high performance and efficiency.

[0019] The battery cells are preferably cylindrical and arranged adjacent to one another along a longitudinal axis and / or radially next to one another. This means that multiple battery cells can be stacked in the axial direction. Alternatively or additionally, multiple battery cells can be arranged side by side in a plane orthogonal to the longitudinal axis. This allows for a flexible and compact design of the interchangeable battery pack.

[0020] The battery cells are particularly preferably designed in the 21700 format.

[0021] Particularly preferably, the connection is a material connection, preferably a laser weld, a resistance weld, a bond, or a soldered connection. This allows for an electrically conductive connection between the battery cells and the cell connector with low electrical resistance while being simple and cost-effective to manufacture.

[0022] Preferably, the connection has multiple contact points per pole of each battery cell. The battery cells are electrically connected to the cell connector at the contact points. This allows defined connection points to be provided between the cell connector and the battery cell, which has a beneficial effect on the mechanical connection between the cell connector and the battery cell, as well as low electrical resistance and simple and cost-effective manufacturing.

[0023] Further preferably, all contact points of the connection are arranged at least a predetermined first distance from a center point of the respective pole of the corresponding battery cell. Preferably, each pole is located on an axial end face of the corresponding battery cell. In particular, the center point corresponds to a center of the preferably circular end face. In other words, a prohibited zone is defined which corresponds to an area with a radius corresponding to the first distance, within which none of the contact points are arranged. In other words, the contact points are widely distributed across the cell cross-section. This makes it possible to provide an optimal current flow from the battery cell to the cell connector and thus a low contact resistance, which can particularly advantageously enable the low AC internal resistance of the interchangeable battery pack.

[0024] Particularly preferably, the first distance at the positive pole is at least 2 mm, preferably at least 3 mm. Alternatively or additionally, the first distance at the negative pole is at least 3 mm, in particular at least 4 mm. This advantageously allows for a greater distance between the contact points and the center point at the larger negative pole, thus enabling a wider distribution of the contact points across the pole.

[0025] Preferably, all contact points are arranged at least a predetermined second distance from each other. The second distance is preferably at least 2 mm, in particular at least 3 mm. This means that all contact points also have a predetermined minimum distance from each other to ensure a broad distribution of the contact points across the surface of the respective pole of the battery cell. This further promotes optimal current flow and low contact resistance.

[0026] Preferably, the at least one cell connector is designed as a sheet metal, which preferably has a thickness of at least 0.1 mm, preferably of at least 0.2 mm, in particular a maximum of 0.5 mm, and preferably a cross-sectional area of ​​at least 0.5 mm 2 , preferably at least 4 mm 2 , in particular a maximum of 15 mm 2 . Particularly preferably, the sheet metal, i.e., the cell connector, is made of copper or a copper alloy, or of steel. This allows efficient current transmission through the cell connector to be provided, enabling the low AC internal resistance.

[0027] The cell connector preferably has a contact region on which the contact points are arranged, and a base region which is connected to the contact region. The contact region and the base region are preferably formed together as a one-piece component. The base region is arranged at a predetermined third distance from the contact region with respect to the axial direction. In other words, the base region and contact region are arranged offset from one another in the axial direction of the battery cell, in particular such that the contact region is arranged closer to the pole of the battery cell than the base region. For example, this can be provided by means of an offset between the base region and the contact region. This makes it possible to provide a defined design which reliably ensures electrical contact exclusively at the contact region with a particularly simple and cost-effective geometry of the cell connector.For example, this can also ensure a certain distance between the base area and the pole so that unintentional contact with the pole can be avoided.

[0028] Furthermore, the invention leads to a consumer, in particular a power tool, comprising the described interchangeable battery pack.

[0029] Preferably, the consumer comprises at least one electric motor, wherein the interchangeable battery pack is configured to provide electrical energy for the at least one electric motor.

[0030] Short description of the drawings

[0031] The invention is described below using exemplary embodiments in conjunction with the figures. In the figures, functionally identical components are identified by the same reference numerals. Here:

[0032] Figure 1 is a perspective view of an interchangeable battery pack according to a first embodiment of the invention,

[0033] Figure 2 shows a detailed view of the interchangeable battery pack of Figure 1,

[0034] Figure 3 is an enlarged detail of Figure 2, and

[0035] Figure 4 shows a detailed view of an interchangeable battery pack according to a second embodiment of the invention.

[0036] Preferred embodiments of the invention Figure 1 shows a perspective view of an interchangeable battery pack 1 according to a first embodiment of the invention. Figures 2 and 3 show detailed views of the interchangeable battery pack 1 of Figure 1.

[0037] The interchangeable battery pack 1 serves as an electrical energy storage device for a consumer (not shown), such as a preferably hand-operated power tool. Preferably, at least one electric motor of the consumer can be powered by the electrical energy stored in the interchangeable battery pack 1. The interchangeable battery pack 1 can be releasably connected to a tool part of the consumer by means of a connection mechanism (not described in detail). This allows the interchangeable battery pack 1 to be replaced, for example, with an identical interchangeable battery pack 1.

[0038] An electrical connection between the interchangeable battery pack 1 and the other components, such as the electric motor, of the consumer is made by means of contact elements 11, 12 on the interchangeable battery pack 1. Preferably, a different electrical potential is present at the two contact elements 11, 12.

[0039] The removable battery pack 1 further comprises several battery cells 2 and several cell connectors 4 (see Figure 2). The battery cells 2 and cell connectors 4 are housed within a housing 50 (see Figure 1), which is provided for protection. The battery cells 2 can also be held in position relative to one another by means of a cell holder 60.

[0040] The battery cells 2 are designed as cylindrical lithium-ion cells in the 21700 format. In the removable battery pack 1, all battery cells 2 are arranged parallel to one another, i.e., parallel to a longitudinal axis 15.

[0041] A plurality of battery cells 2 are electrically connected to one another by means of the cell connectors 4. The cell connectors 4 are designed as copper sheets, which preferably have a thickness of at least 0.1 mm, and in particular a cross-sectional area of ​​at least 1 mm 2The interchangeable battery pack 1 of the first exemplary embodiment comprises a total of 15 battery cells 2, which are electrically connected to one another by means of the cell connectors 4 in such a way as to provide a so-called 5s3p configuration. This means that five battery cells 2 are electrically connected in series, and at the same time, three battery cells 2 are electrically connected in parallel.

[0042] The battery cells 2 are electrically connected to the two contact elements 11, 12 via the cell connectors 4.

[0043] The respective different poles 21, 31 of the battery cells 2, namely the positive pole 21 and the negative pole 31, are arranged on the two axial end faces of the battery cells 2. Each pole 21, 31 is electrically connected to one of the cell connectors 4 by means of a connection 5. Each connection 5 preferably has several resistance-welded connections.

[0044] At the positive poles 21, the cell connectors 4 are preferably configured such that they have a contact region 41, which is preferably circular and, in particular, concentric with the positive pole 21. Furthermore, the cell connectors 4 at the positive pole 21 comprise a base region 42 that surrounds the contact region 41. With respect to the direction of the longitudinal axis 15, the contact region 41 is arranged closer to the positive pole 21 at a predetermined distance, for example, of at least 0.5 mm, from the base region 42.

[0045] At each pole 21, 31, the corresponding connection 5 has several contact points 51, at which the corresponding pole 21, 31 of the battery cell is electrically connected to the cell connector 4. A separate resistance weld connection is provided at each of the contact points 51.

[0046] In the illustrated embodiment, exactly four contact points 51 are provided per pole 21, 31. Alternatively, a different number of contact points 51 may also be provided, for example, exactly two contact points 51. The contact points 51 are arranged such that they are located at least at a predetermined first distance 52 from a center point 25 of the respective pole 21, 31 (see Figure 3).

[0047] The first distance 52 is preferably at least 3 mm at the positive pole 21. A wider distribution of the contact points 51 can be enabled at the negative pole 31, so that the first distance 52 at the negative pole 31 is preferably at least 4 mm. In other words, a prohibition zone is defined around the center point 25 of the respective pole 21, 31, within which none of the contact points 51 are located.

[0048] In addition, all contact points 51 are arranged at at least a predetermined second distance 53 from each other. The second distance 53 is at least 3 mm.

[0049] By arranging the contact points 51 according to the predetermined distances 52, 53, the contact points 51 can be distributed as widely or extensively as possible across the respective poles 21, 31. In particular, the current can be tapped as widely as possible across the poles 21, 31, so that an optimal current flow from the battery cell 2 to the cell connector 4 can be provided with the lowest possible contact resistance.

[0050] In the illustrated embodiment, the cell connectors 4 are slotted. This allows for simplified production of the connections 5 by means of resistance welding. Particularly when using an alternative connection method, cell connectors 4 can also be provided without a slot.

[0051] In the removable battery pack 1, the battery cells 2, the cell connectors 4, and all connections 5 are specially designed such that the total AC internal resistance of the entire removable battery pack 1 is a maximum of 7 milliohms. The total AC internal resistance of the removable battery pack 1 is defined between the first contact element 11 and the second contact element 12.

[0052] This allows the removable battery pack 1 to be provided with particularly high performance. In particular, a particularly high power output to, for example, other components of the consumer is enabled. Specifically, high power outputs, for example, through larger currents, can be drawn from the removable battery pack 1. At the same time, the heating of the removable battery pack 1 can be kept to a minimum, thereby also increasing the service life of the removable battery pack 1.

[0053] Figure 4 shows a detailed view of a removable battery pack 1 according to a second exemplary embodiment of the invention. The second exemplary embodiment essentially corresponds to the first exemplary embodiment of Figures 1 to 3, with the difference of an alternative number of battery cells 2. In the second exemplary embodiment, the removable battery pack 1 comprises a total of five battery cells 2, with all battery cells 2 being electrically connected in series to one another by means of the cell connectors 4. This means that the removable battery pack 1 of the second exemplary embodiment is designed in a so-called 5s1p configuration.

[0054] This makes it possible to provide an interchangeable battery pack 1 with alternative electrical capacity, whereby a particularly compact design can advantageously be made possible.

[0055] In the second exemplary embodiment, the smaller number of battery cells 2 compared to the first exemplary embodiment inherently results in a higher internal AC resistance. In particular, in the second exemplary embodiment, the battery cells 2, the cell connectors 4, and all connections 5 are designed to provide a total internal AC resistance of the interchangeable battery pack 1 of a maximum of 21 milliohms. This allows for optimal performance of the interchangeable battery pack 1, for example, given the number of battery cells 2 and / or the given geometric size.

Claims

Claims 1. Replaceable battery pack for a consumer, in particular for a power tool, comprising: - at least two battery cells (2), - at least one cell connector (4), and - a first contact element (11) and a second contact element (12) for the electrical connection of the interchangeable battery pack (1), - wherein each battery cell (2) is electrically connected to the at least one cell connector (4) by means of a connection (5), and - wherein the battery cells (2) and the at least one cell connector (4) and each connection (5) are designed such that a total AC internal resistance of the interchangeable battery pack (1) between the first contact element (11) and the second contact element (12) is a maximum of 40 milliohms.

2. Exchangeable battery pack according to claim 1, wherein the battery cell (2) and the at least one cell connector (4) and each connection (5) are designed such that the total AC internal resistance is a maximum of 30 milliohms, in particular a maximum of 21 milliohms.

3. Interchangeable battery pack according to one of the preceding claims, wherein a plurality of battery cells (2) are electrically connected to one another in series and / or electrically in parallel by the at least one cell connector (4).

4. Interchangeable battery pack according to claim 3, wherein five battery cells (2) are connected to one another in series, in particular wherein the AC internal resistance is a maximum of 21 milliohms, preferably a maximum of 16 milliohms, in particular a maximum of 11 milliohms.

5. Interchangeable battery pack according to claim 3, wherein five battery cells (2) are connected in series and two battery cells (2) are connected in parallel, in particular wherein the AC internal resistance is a maximum of 12 milliohms, preferably a maximum of 9 milliohms, in particular a maximum of 6 milliohms.

6. Interchangeable battery pack according to claim 3, wherein five battery cells (2) are connected in series and three battery cells (2) are connected in parallel, in particular wherein the AC internal resistance is a maximum of 7 milliohms, preferably a maximum of 6 milliohms, in particular a maximum of 4 milliohms.

7. Interchangeable battery pack according to one of the preceding claims, wherein the battery cells (2) are designed as lithium-ion battery cells.

8. Interchangeable battery pack according to one of the preceding claims, wherein the connection (5) is a material connection, in particular a laser welded connection, or a resistance welded connection, or a bonded connection, or a soldered connection.

9. Exchangeable battery pack according to one of the preceding claims, wherein the connection (5) has a plurality of contact points (51) per pole (21, 31) of each battery cell (2), wherein the battery cells (2) are electrically conductively connected to the cell connector (4) at the contact points (51).

10. Interchangeable battery pack according to claim 9, wherein all contact points (51) are arranged at least a predetermined first distance (52) from a center point (25) of the respective pole (21, 31).

11. Interchangeable battery pack according to claim 10, wherein the first distance (52) at the positive pole (21) is at least 2 mm, preferably at least 3 mm, and / or wherein the first distance (52) at the negative pole (31) is at least 3 mm, in particular at least 4 mm.

12. Interchangeable battery pack according to claim 10 or 11, wherein all contact points (51) are at least a predetermined second distance (53) from each other are arranged, in particular wherein the second distance (53) is at least 2 mm, preferably at least 3 mm.

13. Exchangeable battery pack according to one of the preceding claims, wherein the at least one cell connector (4) is designed as a sheet metal, which preferably has a Thickness of at least 0.1 mm, preferably at least 0.2 mm, in particular a maximum of 0.5 mm, preferably a cross-sectional area of ​​at least 0.5 mm 2 , preferably at least 4 mm 2 , in particular a maximum of 15 mm 2 , and which is particularly preferably made of copper or a copper alloy or steel.

14. The interchangeable battery pack according to claim 13, wherein each cell connector (4) has a contact region (41) on which the contact points (51) are arranged, and a base region (42) connected to the contact region (41), and wherein the base region (42) is arranged at a predetermined third distance with respect to the axial direction.

15. Consumer, in particular power tool, comprising a replaceable battery pack (1) according to one of the preceding claims.

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