Storage battery pack

Abstract

The invention relates to a battery pack, in particular an exchangeable battery pack, comprising a housing in which at least one battery cell is received, the battery pack having at least two parts which lie against one another and are connected in a force-fitting manner. According to the invention, at least one component, in particular two components, has a surface modification which is designed to increase the contact force between the components.

Description

TECHNICAL FIELD

[0001] The application relates to a battery pack. BACKGROUND

[0002] A battery device having a plurality of battery cells is described in DE 10 202020 1165 A1, wherein a tensioning anchor is provided for applying a pretension to the battery pack. SUMMARY

[0003] The application relates to a battery pack, in particular a replaceable battery pack, having a housing in which at least one battery cell is received, wherein the battery pack has at least two components which abut one another and are connected to one another in a force-locking manner. It is proposed that at least one component, in particular both components, have a surface modification The surface modification is configured to increase the contact force between the components. As a result, the stability of the battery pack can be advantageously increased.

[0004] The battery pack is in particular part of a system consisting of a battery pack and an electric consumer, wherein the electric consumer is supplied with electrical energy during operation by the battery pack. The battery pack can be configured for example as a hand-held power tool battery pack or as an e-bike battery pack. The battery pack is in particular configured as a replaceable battery pack, which is preferably detachably connectable to the electric consumer without tools. Alternatively, it is also conceivable that the battery pack is fixedly installed in the housing of the electric consumer or integrated therein. The battery pack is in particular configured to be connectable to a charging device for charging the battery pack. Alternatively or additionally, the battery pack can also be configured such that it can be charged in the state of connection to the electric consumer.

[0005] The electric consumer can be configured in particular as a garden appliance, for example a lawnmower or a pruning shears; as a household appliance, for example an electric window cleaner or a hand-held vacuum cleaner; as a hand-held power tool, for example an angle grinder, a screwdriver, an electric drill, an electric hammer or the like; as an electrically powered means of transport, for example an electric bicycle in the form of a pedal-assisted electric bicycle (Pedelec) or a twist-and-go electric bicycle (E-Bike), an electric scooter; or as a measuring tool, for example a laser distance meter. Furthermore, it is also conceivable that the electric consumer is configured as another, in particular portable, appliance, for example a construction site light, a vacuum cleaner or a construction site radio.

[0006] A battery pack has a housing in which individual battery cells are received. The housing of the battery pack is preferably constructed as an outer shell. The battery pack, particularly the housing, can be configured to be detachably connected to or fixedly connected to electrical equipment and / or charging devices via a mechanical interface. The housing of the battery pack may have one or more housing portions. The housing has at least one housing portion constructed as an outer shell portion. Preferably, the housing is entirely composed of the outer shell portion. Here, the outer shell portion externally defines the battery pack and is accessible to the user. Furthermore, the housing may have at least one inner housing portion completely surrounded by the at least one housing portion. The housing of the battery pack may be made of metallic materials and / or plastic.

[0007] The battery pack can be force-locked and / or form-locked connected to an electrical appliance via a mechanical interface. Advantageously, the mechanical interface includes at least one actuating element by which the connection between the battery pack and the electrical appliance and / or the charging device can be disengaged. The actuating element can be configured as, for example, a lock, button, lever, or key. The actuating element can be arranged on the battery pack or on the electrical appliance. Furthermore, the mechanical interface may include guiding elements for guiding the battery pack during connection and / or centering elements for centering the battery pack during connection.

[0008] Furthermore, the battery pack has at least one electrical interface through which it can be electrically connected to an electrical appliance and / or a charging device. This electrical connection allows for, for example, charging and / or discharging of the battery pack. Alternatively or additionally, it is conceivable that information can be transmitted from the battery pack to the electrical appliance, and vice versa, via the electrical interface. The electrical interface is preferably configured as a contact interface, in which the electrical connection is achieved through the physical contact of at least two conductive members. The electrical interface preferably includes at least two electrical contact elements. In particular, one electrical contact element is configured as a positive contact, and the other as a negative contact. Additionally, the electrical interface may have at least one additional contact configured to transmit additional information to the electrical appliance and / or charging device. The additional contact may be configured as a signal contact, an encoded contact, a temperature contact, a bus contact, etc. The electrical contact element may, for example, be configured as a spring-loaded contact element in the form of a tulip-shaped contact or a face contact in the form of a contact blade. Alternatively or additionally, the electrical interface may have a secondary charging coil element for inductive charging. The mechanical and electrical interfaces may be constructed integratedly or separately from each other.

[0009] In particular, the battery pack incorporates electronic components. These electronic components may include, for example, circuit boards, computing units, control units, transistors, capacitors, sensor elements, light-emitting diodes, memory units, etc. Additionally or alternatively, it is conceivable that information is retrieved by the electronic components. The electronic components are particularly configured for controlling or regulating the battery pack and / or electrical equipment. The electronic components particularly include a Battery Management System (BMS) configured for monitoring the battery pack. The BMS is particularly configured to prevent overcharging and / or deep discharging of the battery pack. Preferably, the BMS is configured for proper cell balancing. The electronic components may also have one or more sensor elements, such as temperature sensors for determining the temperature within the battery pack or motion sensors for determining motion. The electronic components may alternatively or additionally have encoding elements, such as encoded resistors. Electrical contact elements of the battery pack's electrical interface may be arranged on or connected to the circuit board of the electronic components. In the context of this application, a circuit board should be understood as a circuit carrier having an organic or inorganic substrate (e.g., an IMS). The circuit board can be configured as a rigid circuit board or a flexible circuit board. Furthermore, the circuit board can be an assembled (electronic component) or unassembled (electronic component) circuit board. The circuit board can be constructed with a single layer or multiple layers.

[0010] A single battery cell can be constructed as a primary cell, having a configuration in which one cell electrode is located at one end and another cell electrode is located at the opposite end. In particular, the battery cell has a positive cell electrode at one end and a negative cell electrode at the opposite end. Preferably, the battery cell is constructed as a nickel-cadmium or nickel-metal hydride battery, and particularly preferably as a lithium-based or lithium-ion battery cell. Alternatively, for example, it is conceivable that the battery cell is constructed as a pouch cell or a prismatic cell. The battery voltage of a battery pack is typically a multiple of the voltage of a single battery cell and is determined by the connection method of the battery cells (parallel or series). Thus, for a common 3.6V battery cell, exemplary battery voltages are 3.6V, 7.2V, 10.8V, 14.4V, 18V, 36V, 54V, 108V, etc. Preferably, the battery cell is constructed as a round cell that is at least substantially cylindrical, with the cell electrode arranged at the cylindrical end.

[0011] In the context of this application, the surface-modified part should be understood in particular as a surface-modified part constructed as a single piece with the component. Therefore, the surface-modified part is made of the same material as the component.

[0012] In the context of this application, contact force should be understood in particular as the force required to separate two parts from each other. Contact force is particularly configured as friction.

[0013] Furthermore, it is proposed that at least one component is configured as a cell holder for receiving battery cells, and the cell holder has a surface-modified portion. Alternatively or additionally, one of the components may be configured as an intermediate plate, wherein the intermediate plate has a surface-modified portion.

[0014] The cell retainers of a battery pack are particularly constructed as housing portions, preferably as inner housing portions. However, it is also conceivable that the cell retainers are partially or completely constructed as outer housing portions. The battery pack housing may have one or more cell retainers. Housing portions, especially cell retainers, are force-locked, form-locked, and / or material-locked connected to each other. Cell retainers are preferably made of plastic, especially hard plastic, preferably thermoplastic. Cell retainers are preferably made of high-temperature resistant plastic, preferably fiber-reinforced plastic. Alternatively, it is also conceivable that cell retainers are made of metallic materials. Cell retainers are particularly formed integrally or as a single piece. Other materials, such as ceramics, are also considered. In the context of this application, "single piece" should be understood in particular as a single component constructed from a single material, rather than composed of multiple components connected to each other by material locking and / or force locking and / or form locking. Thus, a single-piece component is constructed from a single material. In the context of this application, "integrated" should be understood as multiple components that are material-lockingly connected to each other (e.g., by two-component injection molding or material locking). Therefore, an integral component can be made of one or more materials. Alternatively, it is also conceivable that the cell retainer is constructed in multiple parts, wherein the different parts are force-locking and / or form-lockingly connected to each other. A battery pack has multiple cell retainers arranged side-by-side and / or front-to-back.

[0015] The intermediate plate is specifically constructed as an inner shell portion, which is arranged on the end sides of one or two individual retainers. The intermediate plate is preferably partially and directly abutted against one or more individual retainers. The intermediate plate is preferably made of the same material as the individual retainers, although other materials such as plastics, metals, or ceramics are also considered.

[0016] Furthermore, it is proposed that at least one component is configured as a cell connector for electrical contact of a battery cell, wherein the cell connector has a surface-modified portion. The cell connector is configured for electrical contact of at least one battery cell. The cell connector preferably rests against the battery cell, particularly against a conductive area of ​​the battery cell, such as the cell electrode. The cell connector can be made, for example, of a metal sheet, cable, or wire. Preferably, the cell connector is made of a metal sheet, wherein the cell connector partially or substantially completely covers at least one, preferably multiple, battery cells on its end side. The cell connector is preferably constructed as a single piece or integral unit. The cell connector is preferably made of aluminum, steel, copper, or nickel, or an alloy comprising at least one of these materials. The cell connector may have a spring element for locally enhancing the elasticity of the cell connector, wherein the spring element is particularly constructed as a single piece with the cell connector. Additionally, the cell connector may have a fuse.

[0017] Furthermore, it is proposed that the surface modification section be constructed as a region with increased roughness, wherein the roughness depth is at least 10 μm, particularly at least 15 μm, and preferably at least 20 μm. This allows for advantageous further optimization of the contact force. The roughness depth is preferably classified according to VDI standard 3400. The roughness depth can be classified into Rmax level or Rz level. Here, in the Rmax level, the maximum roughness depth of the surface is determined, regardless of the average roughness depth. In the Rz level, the average roughness depth is determined.

[0018] Furthermore, it is proposed that the surface-modified portion has multiple interlocking structural elements that, in the connected state, at least partially penetrate the corresponding component. This advantageously optimizes the contact force. The interlocking structural elements are preferably configured such that the surface-modified portion is formed by multiple substantially identical interlocking structural elements. Alternatively, it is conceivable that the interlocking structural elements are constructed randomly and without limitation.

[0019] Furthermore, it is proposed that the interlocking structural elements be constructed in a pyramidal and / or triangular shape. This can advantageously further optimize the contact force.

[0020] Furthermore, it is proposed that the surface-modified portion is manufactured using electro-erosion technology. This allows for the advantageous and cost-effective application of the surface-modified portion to the component. Attached Figure Description

[0021] Other advantages are apparent from the following description of the accompanying drawings. The drawings and description contain multiple combinations of features. Those skilled in the art can also appropriately view these features individually and combine them into other meaningful combinations.

[0022] The diagram shows:

[0023] Figure 1 A perspective view of an electric bicycle with a battery pack is shown.

[0024] Figure 2 A perspective view of an exemplary battery pack is shown;

[0025] Figure 3 A perspective view of a cell retainer for a battery pack is shown, which is connected to an intermediate plate via a surface-modified portion;

[0026] Figure 4a A schematic diagram of one possible implementation of the surface modification section is shown;

[0027] Figure 4b A schematic diagram of two components connected to each other without surface modification is shown;

[0028] Figure 5 A schematic diagram of a cell connector for a battery pack is shown, which connects to the battery cell via a surface-modified portion. Detailed Implementation

[0029] exist Figure 1 The diagram shows an electrical device 10 with a battery pack 100 in a perspective side view. The electrical device 10 is exemplarily constructed as an electrically driven vehicle 12, particularly an electric bicycle 14. The electric bicycle 14 can be constructed, for example, as a pedal-assist electric bicycle or a lever-operated electric bicycle.

[0030] The electric bicycle 14 has a frame 18, or bicycle frame. Two wheels 20 are connected to the frame 18. Furthermore, the electrical device 10 has a drive unit 22, which includes an electric motor. The electric motor is preferably constructed as a permanent magnet excited brushless DC motor. The motor is exemplaryly constructed as a mid-drive motor, although a hub motor or similar type is also conceivable.

[0031] The drive unit 22 includes a control unit (not shown) configured to control or regulate the electric bicycle 14, particularly the electric motor. The electric bicycle 14 has a pedal crank 24. The pedal crank 24 is connected to a pedal crank shaft (not shown).

[0032] The control unit and the drive unit 22, which includes a motor and a foot crankshaft, are arranged in a drive housing 26 connected to the frame. The drive motion of the motor is preferably transmitted to the foot crankshaft via a transmission (not shown), wherein the auxiliary force of the drive unit 22 is controlled or adjusted by the control unit.

[0033] Electrical device 10 is electrically and mechanically connected to a battery pack 100 configured to provide power to drive unit 22. The battery pack 100 is exemplarily configured as a replaceable battery pack 102. In the connected state, the battery pack 100 is exemplarily fully received within the frame 18 of the electric bicycle 14. This connection can be achieved by axially inserting the battery pack 100 into the downtube of the frame 18, or by pivoting the battery pack 100 laterally into the frame 18. Alternatively, it is conceivable that the battery pack 100 can be fixed to the outside of the frame 18, for example, to the downtube or seat tube of the frame 18.

[0034] exist Figure 2 The diagram shows a perspective view of a battery pack 100. The battery pack 100 has a housing 104 constructed as an outer shell. The housing 104 exemplarily has a base 105 extending between two end plates 103, wherein the end plates 103 close the base 105 at its ends. The base 105 exemplarily has a rectangular cross-section and extends substantially along the entire length of the battery pack 100. The base 105 exemplarily is made of a metallic material (e.g., aluminum). The end plates 103 of the housing 104 exemplarily are made of plastic, particularly hard plastic.

[0035] The battery pack 100 has a power status indicator 106 disposed on the housing 104 of the battery pack 100 and configured to indicate the power status of the battery pack 100. Furthermore, the housing 104 of the battery pack 100 is connected to two connecting plates 108. The connecting plates 108 are exemplarily screwed to the housing 104 of the battery pack 100, but it is also conceivable that the connecting plates 108 are connected to the housing 104 by other connection methods, or that they are a single piece of the housing 104 of the battery pack 100. Here, the first connecting plate 110 includes a locking unit 113, which can be connected to a corresponding locking unit (not shown) of the electric bicycle 14. The second connecting plate 112 includes an electrical interface (not shown) for electrically connecting the battery pack 100 to the electric bicycle 14. It is also conceivable that the connecting plates 108 and the end plates 103 are single pieces of the same construction or integrally formed with each other.

[0036] exist Figure 3 The diagram shows cell retainers 200 arranged in the housing 104 of a battery pack 100. The battery pack 100 exemplarily has five cell retainers 200, with intermediate plates 210 arranged between the cell retainers 200. Exemplarily, an intermediate plate 210 is arranged on each end side of the cell retainer 200 of the battery pack 100, the intermediate plate closing the cell retainer 200 at the end side. The cell retainers 200 and the intermediate plates 210 are exemplarily made of plastic, particularly hard plastic.

[0037] A cell holder 200 is used to receive battery cells 202. The cell holder 200 is exemplarily configured to receive ten battery cells 202. Each battery cell 202 is exemplarily configured as a cylindrical circular cell extending between two cell electrodes 220 along its longitudinal direction (see [link to documentation]). Figure 5 ).

[0038] The cell holder 200 is configured to receive individual cells separately, such that the battery cells 202 are individually and separately arranged in separate individual cell receiving portions 204. The cell holder 200 is exemplarily made of plastic, particularly glass fiber reinforced rigid plastic. The cell holder 200 is further constructed in two parts, although a single-piece construction is also conceivable.

[0039] The battery pack 100 also has cell connectors 206 for electrical connection of the individual battery cells 202. Exemplarily, each battery cell 202 is connected to the cell connector 206, particularly at its end electrode 220. The cell connector 206 is exemplarily made of a metallic material, especially a metal sheet. The battery cells 202 are connected in parallel or series with each other via the cell connectors 206. The cell connector 206 is exemplarily configured such that it is force-locked and detachably connected to the battery cells 202. Here, a preload is applied by an elastic spring element 208, exemplarily constructed of foam material 209, especially Poron (polyurethane foam), wherein the elastic spring element 208 rests directly against the cell connector 206 in the connected state and under deformation. The elastic spring element 208 is exemplarily arranged on an intermediate plate 210. The intermediate plate 210 is integrally constructed, wherein the elastic spring element 208 is locked to a substrate 211 material made of rigid plastic.

[0040] Individual retainers 200 are axially pressed together by fastening elements (exemplarily configured as tension anchors), not shown. In the installed state, individual retainers 200 directly abut against the contact surface 214 of the intermediate plate 210 via contact surface 211. The contact surface 214 of the intermediate plate 210 extends continuously along the contour of the intermediate plate 210, exemplarily. The contact surface 211 of individual retainer 206 extends intermittently along the contour of individual retainer 206, exemplarily.

[0041] The cell retainer 200 and the intermediate plate 210 each have a surface modification portion 212, which is used to increase the contact force between the components 215 of the battery pack 100 in the form of the cell retainer 200 and the intermediate plate 210.

[0042] The surface-modified portion 212 is exemplarily constructed as a micro-tooth portion 216, and in Figure 4aThe diagram illustrates the surface modification portion 212, particularly the micro-tooth portion 216, and the corresponding component 215 as a single piece. Exemplarily, the surface modification portion 212, particularly the micro-tooth portion 216, can be manufactured using a targeted electro-erosion technique. Here, the surface modification portion 212 is configured such that the roughness depth (especially according to the Rz grade) is in the range of 18 to 20 micrometers. The micro-tooth portion 216 is here constructed non-limitingly and randomly.

[0043] Advantageously, the surface modification portion 212 of component 215 significantly improves contact force, especially torsional stiffness, thereby also reducing the thickness of the component. Figure 4b For comparison, two components 215a are shown, each with a standard and significantly smaller roughness depth on its contact surfaces 211a and 214a. To achieve the same contact force (especially torsional stiffness), these components would require a significantly greater material thickness.

[0044] exist Figure 5 The diagram shows a schematic of the single-cell connector 206 in the state of being connected to the single-cell electrode 220 of the battery cell 202.

[0045] The individual cell receiving portion 204 of the cell holder 200 exemplarily has a radial fastening element 222, which is configured to radially fasten the battery cell 202 in the cell holder 200. The radial fastening element 222 is preferably made of elastic plastic, such as soft plastic.

[0046] The individual retainer 200 also has a fixing support 224, wherein the fixing support 224 is exemplary monolithically constructed with the individual retainer 200. The fixing support 224 is exemplary constructed as a pin 226, which is inserted into a corresponding slot of the individual connector 206 and exemplary holds the individual connector 206 in a direction substantially perpendicular to the plane of the individual connector 206 in a form-locking manner.

[0047] The single-unit connector 206 also has a relative clearance compensation element 228, which is used to compensate for the clearance between the components 215 in the form of the battery cell 202 and the single-unit connector 206 that are force-locked together. The relative clearance compensation element 228 is exemplary monolithically constructed with the single-unit connector 206, and is implemented in particular by means of targeted material weakening portions achieved by means of slots.

[0048] The single-cell connector 206 has a contact area 230 in which it directly abuts against the single-cell electrode 220 of the battery cell 202. On the side facing the battery cell 202, the single-cell connector 206 has a surface-modified portion 212 in the contact area 230 to increase the contact force.

[0049] The surface modification portion 212 of the single-cell connector is exemplarily configured as an engagement structure element 232. The engagement structure element 232 is particularly configured as a micro-clamping portion 234. Preferably, the single-cell connector 206 is made of a material harder than the single-cell electrode 220 of the battery cell 202, such that the micro-clamping portion 234 clamps into the single-cell electrode 220 under the action of a force in the direction toward the battery cell 202, in that the micro-clamping portion 234 is preferably embedded in a softer surface layer of the single-cell electrode 220.

[0050] The micro-clamping portion 234 is exemplarily constructed as a pyramid shape with a triangular structure, although other structures are also conceivable. Advantageously, unlike material-locking connections achieved through conventional welding processes, such as between battery cells and cell connectors, the micro-clamping portion requires no process heat. Therefore, the clamping portion significantly increases the contact force (especially friction) between the cell connector 206 and the battery cell 202, resulting in a significantly optimized force-locking engagement between components 215, thereby enabling a releasable connection.

Claims

1. A battery pack, particularly a replaceable battery pack, having a housing (104) in which at least one battery cell (202) is received, wherein, The battery pack (200) has at least two components (215) that are attached to each other and forcefully connected to each other. Its features are, At least one of the components (215), particularly two of the components (215), has a surface modification portion (212) configured to improve the contact force between the components (215).

2. The battery pack according to claim 1, characterized in that, At least one of the components (215) is configured as a cell holder (206) for receiving a battery cell (202) and has the surface modification portion (212).

3. The battery pack according to any one of the preceding claims, characterized in that, At least one of the components (215) is configured as an intermediate plate (210) and has the surface modification part (212).

4. The battery pack according to any one of the preceding claims, characterized in that, At least one of the components (215) is configured as a cell connector (206) for electrical contact of a battery cell (202).

5. The battery pack according to any one of the preceding claims, characterized in that, The surface modification section (212) is configured as a region with increased roughness, wherein the roughness depth is at least 10 micrometers, particularly at least 15 micrometers, and preferably at least 20 micrometers.

6. The battery pack according to any one of the preceding claims, characterized in that, The surface-modified part (212) has a plurality of interlocking structural elements (232) that, in the connected state, at least partially penetrate into the corresponding component (215).

7. The battery pack according to any one of the preceding claims, characterized in that, The occlusal structural element (232) is constructed in a pyramid shape and / or a triangle shape.

8. The battery pack according to any one of the preceding claims, characterized in that, The surface modification part (212) is manufactured by electro-erosion technology.

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