Battery module with improved measurement connection and use thereof

Abstract

The invention relates to a battery module (1) with a plurality of battery cells and a battery management system (3) for monitoring and controlling the charging and discharging process, wherein the battery cells are electrically connected in series and / or in parallel by means of electrically conductive cell connectors (2) in an electrically conductive force-fitting and / or material-fitting connection with the respective battery poles of the battery cells, wherein the cell connectors (2) form a measuring contact surface (2c) for producing a detachable measuring electrical connection to the battery management system (3), and the battery management system (3) forms an electrical connection surface (3f) and has electrically conductive contact springs (3b) which are in a material-fitting connection with the connection surface (3f) and form spring tongues (3c) which force-fittingly and slidingly abut the measuring contact surface (2c) in order to produce a detachable measuring electrical connection of the cell connectors (2) to the battery management system (3) and in order to avoid mechanical stresses; the invention also relates to the associated use.

Description

Technical Field

[0001] The present invention relates to a battery module having multiple battery cells and a battery management system for monitoring and controlling the charging and discharging process, wherein the battery cells are electrically connected in series and / or in parallel by means of one or more cell connectors. Background Technology

[0002] Battery modules are known, for example, from EP 2 744 033 A1. These battery modules include a housing in which multiple battery cells are arranged. These battery cells are, in most cases, assembled in multiple layers and their temperature is regulated by cooling elements arranged within the housing, which are in thermal contact with the individual electrodes of the battery cells or the battery. As shown in EP2 744 033 A1, multiple battery cells are often assembled into a generally cuboid battery block. The aim is to achieve the highest possible assembly density. Furthermore, the individual cell blocks should be as stable as possible to facilitate easy operation. On the other hand, it is necessary to continuously monitor various parameters of the battery cells and / or cell blocks, such as their voltage or temperature, via a battery management system to ensure long-term and safe operation. Soldering is chosen as a common connection technique between electrical terminals because it creates a long-term stable and vibration-resistant material fit connection between the electrical terminals of the battery cells. The disadvantage of this method is that such connections can no longer be non-destructively disassembled. Additionally, electrical measurement connections to the required battery management system often require additional cabling, leading to higher costs and creating additional sources of error. However, there is a need for the following: especially the ability to replace the battery management system without disassembling the material mating connections, i.e., to design the required measurement connections to make safe contact with the battery cells or the cell connectors that connect these battery cells and to be detachable.

[0003] Generally speaking, another important aspect of manufacturing corresponding battery modules is ensuring the most efficient and flexible manufacturing possible. Another issue is facilitating the as non-destructive disassembly of the battery module as possible, especially for recycling processes. Summary of the Invention

[0004] The object of this invention is to provide a battery module with a battery management system, which can be manufactured more simply and efficiently, can be maintained and recycled more easily, at a lower cost, and without damage, and offers improved operational safety. This object is achieved by the battery module according to claim 1. The subject matter of the parallel claims is also advantageous. Advantageous designs are the subject matter of the dependent claims. It should be noted that the features individually detailed in the claims can be combined with each other in any technically meaningful manner and demonstrate other designs of the invention. The description, in particular, is appended with the drawings to characterize and describe the invention in detail.

[0005] This invention relates to a battery module having multiple battery cells and a battery management system for monitoring and controlling the charging and discharging process. The battery module according to the invention allows for freely selectable series and / or parallel connection of battery cells, preferably lithium-ion cells, but not limited to this cell configuration. Series or parallel connection is achieved by means of one or more cell connectors. The cell connectors are configured to electrically connect the battery terminals of the battery cells, wherein the connection is force-fitted and / or material-fitted. In most cases, the battery cells are preferably prismatic or so-called rigid-case cells. This or these cell connectors according to the invention (especially when they are to carry large currents) are formed, for example, from rigid metal parts such as copper plates, brass plates, or aluminum plates and are referred to as busbars. The cell connectors can also be formed as circuit boards. The cell connectors are connected to the battery terminals of the battery cells, for example, by force-fitting or material-fitting. The cell connectors form measurement contact surfaces to create a detachable measurement electrical connection with the battery management system.

[0006] The battery management system according to the invention includes, for example, a voltage measuring device and / or a temperature measuring device to measure at least one voltage or temperature of one or more specific battery cells. According to the invention, the battery management system forms an electrical connection surface and has a conductive contact spring that mates with the connection surface material and forms a spring tongue. The spring tongue engages to create a detachable measuring electrical connection between the cell connector and the battery management system and slides against the measuring contact surface to avoid mechanical stress. The detachable connection allows for easy and non-destructive replacement of the battery management system, while the pre-tightened electrical connection provides reliable contact even under temperature fluctuations and tolerance compensation during installation and operation.

[0007] The contact spring is formed of spring bronze, for example, as a stamped part. The contact spring has one or more coatings, for example. These coatings are, for example, a copper alloy as a base layer, a diffusion barrier layer as a nickel layer, for example, as an intermediate layer, and a highly conductive outer contact layer. Here, for example, a silver or gold coating is used as the contact layer.

[0008] Preferably, the measuring contact surface is formed at the planar connector of the battery cell connector, and the connector mates with the base material of the battery cell connector. Alternatively, the measuring contact surface can be directly disposed at the base, thus eliminating the need for a connector. For example, the connector is a copper strip, brass strip, or aluminum strip. Preferably, the connector is welded to the base, and more preferably, the connection is made by laser pulse welding.

[0009] Preferably, the connector is coated with a diffusion barrier layer (e.g., a nickel layer) and a contact layer (e.g., silver or gold).

[0010] Preferably, the connector abuts against the housing of the battery module to provide support and stability. Preferably, the connector is bent, such that the measuring contact surface is arranged to be offset from the surface of the cell connector (especially the surface of the base).

[0011] Preferably, the spring tongue is formed in an arc shape to form a protruding planar section, which engages with the corresponding measuring contact surface in force and / or friction.

[0012] Preferably, the battery management system has a circuit board, and the connection surface is formed in the main surface of the circuit board. Preferably, the free end of the spring tongue is supported on the main surface of the circuit board to ensure a reliable connection and prevent shearing of the contact spring. Preferably, the spring tongue of the contact spring is formed into a ramp shape, particularly in the section following the protruding planar section in the direction toward the free end of the spring tongue.

[0013] Preferably, the protruding planar section is formed to be flat and extends parallel to the main surface of the circuit board to ensure reliable measurement electrical connection.

[0014] According to a preferred design, the contact spring has a foot with a foot base that abuts against the connecting surface, wherein the foot is brazed to the connecting surface, for example by wave soldering or wave pool soldering.

[0015] Preferably, the foot of the contact spring is positioned such that it is covered by the protruding planar section of the spring tongue, thereby achieving a compact contact spring.

[0016] Preferably, the footing surface has a through hole, allowing the contact spring to be joined at the connection surface via a reflow soldering process.

[0017] The present invention also relates to the use of the battery module in one of the above embodiments in a motor vehicle. Attached Figure Description

[0018] The invention and its technical environment will now be explained in detail with the aid of the accompanying drawings. It should be noted that the drawings illustrate particularly preferred embodiments of the invention; however, the invention is not limited to these embodiments. The drawings schematically illustrate: Figure 1 A cross-sectional view of an embodiment of the present invention, showing battery module 1; Figure 2 The battery module 1 is shown in Figure 1A three-dimensional cross-sectional view of the embodiment shown in the figure; Figure 3 The battery module 1 is shown in Figure 1 A perspective view of the contact spring 3b in the embodiment shown; Figure 4 Show Figure 1 The perspective view of the battery cell connector 2 shown. Detailed Implementation

[0019] Figure 1 and Figure 2 An embodiment of the battery module according to the invention is illustrated in the illustrations, each limited to a portion of the battery module 1. The battery module 1 has a plurality of battery cells (not shown in detail) and a battery management system 3 for monitoring and controlling the charging and discharging processes of the battery cells. The battery module 1 according to the invention allows for free series and / or parallel connection of the battery cells, preferably involving lithium-ion cells, but not limited to this cell configuration. A cell connector 2 is configured to electrically connect the battery terminals of the battery cells, wherein this connection is force-fitted and / or material-fitted. This or these cell connectors 2 according to the invention are formed from rigid metal components such as copper, brass, or aluminum plates and are referred to as busbars. The cell connector 2 forms a measuring contact surface 2c to create a detachable measuring electrical connection with the battery management system 3. In the illustrated embodiment, the measuring contact surface 2c is formed at a planar connector 2b of the cell connector 2, which is material-fitted to the base 2a of the cell connector 2, which is formed as a stamped and bent part, by laser pulse welding. The connector 2b is an aluminum strip coated with a diffusion barrier layer (e.g., a nickel layer) and an external contact layer (e.g., silver or gold). The connector 2b is bent such that the measuring contact surface 2c is arranged offset from the surface of the base 2a of the cell connector 2. The connector 2b abuts against the housing 4 of the battery module to provide support and stability for the connector 2b.

[0020] To monitor and control the charging and discharging process of the battery cells, the battery management system 3 has a circuit board 3a and multiple voltage and / or temperature measuring devices implemented by electronic components. These voltage and / or temperature measuring devices are used to measure at least one voltage or temperature of one or more specific battery cells. Additionally, the battery management system 3 forms an electrical connection surface 3f disposed on the main surface of the circuit board 3a. The battery management system 3 also includes a conductive contact spring 3b, which is materially mated (in this case, brazed) with the connection surface 3f and forms a separate spring tongue 3c. This spring tongue forcefully abuts against the measuring contact surface 2c to create a detachable measuring electrical connection between the cell connector 2 and the battery management system 3, and slides against the measuring contact surface 2c to avoid mechanical stress. The detachable connection allows for easy and non-destructive replacement of the battery management system 3, while the pre-tightened electrical connection provides reliable contact even under temperature fluctuations and tolerance compensation during installation and operation. The contact spring 3b is made of spring bronze as a stamped part and... Figure 4 This is illustrated in detail. The contact spring, for example, has one or more coatings. These coatings may be, for example, a copper alloy as a base layer, a diffusion barrier layer as a nickel layer (e.g., an intermediate layer), and a highly conductive outer contact layer. Here, for example, a silver or gold coating may be used as the contact layer. Figure 3 As shown, the spring tongue 3c of the contact spring 3b is formed in an arc shape to form a protruding planar section 3d, which engages with the corresponding measuring contact surface 2c in force and / or frictional engagement.

[0021] like Figure 1 and Figure 2 As shown, the free end 3e of the spring tongue 3c is supported on the main surface of the circuit board 3a to ensure a reliable connection and prevent shearing of the contact spring 3b. Here, the spring tongue 3c contacting the spring 3b is formed and obtained in a substantially straight and sloping shape in the section following the protruding planar section 3d in the direction toward the free end 3e of the spring tongue 3c. The protruding planar section 3d is formed to be flat and extends parallel to the main surface of the circuit board 3a to ensure a reliable measurement electrical connection. Figure 3 As shown, the contact spring 3b has a foot 3h with a foot having a support surface that abuts against the connection surface 3f of the circuit board 3a, wherein the foot 3h is brazed to the connection surface 3f. To save construction space, the support surface of the foot 3h of the contact spring 3b is arranged to be covered by a protruding planar section 3d of the spring tongue 3c. The support surface of the foot 3h of the contact spring 3b has a through hole 3g, allowing the contact spring 3b to be material-fitted to the connection surface 3f of the circuit board 3a through a reflow soldering process.

Claims

1. A battery module (1) having a plurality of battery cells and a battery management system (3) for monitoring and controlling the charging and discharging process, wherein the battery cells are electrically connected in series and / or in parallel by means of conductive cell connectors (2), the cell connectors being electrically connected to the corresponding battery terminals of the battery cells in a conductive force-fit and / or material-fit connection, wherein the cell connectors (2) form a measurement contact surface (2c) for generating a detachable measurement electrical connection with the battery management system (3), and the battery management system (3) forms an electrical connection surface (3f) and has a conductive contact spring (3b), the contact spring being material-fit connected to the connection surface (3f) and forming a spring tongue (3c), the spring tongue being force-fitted against the measurement contact surface (2c) and slidingly abutting against it to avoid mechanical stress in order to generate a detachable measurement electrical connection between the cell connectors (2) and the battery management system (3).

2. The battery module (1) according to claim 1, wherein the measuring contact surface (2c) is formed at the planar connector (2b) of the cell connector (2), and the connector is materially mated with the base (2a) of the cell connector (2).

3. The battery module (1) according to the preceding claim, wherein the connector (2b) is welded to the base (2a), preferably by laser pulse welding.

4. The battery module (1) according to any one of claims 2 or 3, wherein the connector (2b) is a surface-coated metal strip, such as an aluminum strip.

5. The battery module (1) according to any one of claims 2 to 4, wherein the connector (2b) abuts against the housing (4) of the battery module (1).

6. The battery module (1) according to any one of claims 2 to 5, wherein the connector (2b) is bent such that the measuring contact surface (2c) is arranged to be offset from the surface of the cell connector (2).

7. The battery module (1) according to any one of the preceding claims, wherein the spring tongue (3c) of the contact spring (3b) is formed in an arc shape to form a protruding planar section (3d), the protruding planar section engaging with the measuring contact surface (2c) in force and / or friction engagement.

8. The battery module (1) according to any one of the preceding claims, wherein the battery management system (3) has a circuit board (3a) and the connection surface (3f) is formed on the main surface of the circuit board.

9. The battery module (1) according to the preceding claim, wherein the free end (3e) of the spring tongue (3c) is supported on the main surface of the circuit board (3a).

10. The battery module (1) according to the preceding claim, wherein the spring tongue (3c) of the contact spring (3b) is formed as a ramp in the section following the protruding planar section (3d), particularly in the direction toward the free end (3e) of the spring tongue (3c).

11. The battery module (1) according to any one of the preceding claims, wherein the protruding planar segment (3d) of the spring tongue (3c) of the contact spring (3b) is formed to be flat and extend parallel to the main surface of the circuit board (3a).

12. The battery module (1) according to any one of the preceding claims, wherein the spring tongue (3c) of the contact spring (3b) stands on a foot (3h) having a foot surface abutting the connecting surface (3f), and the foot (3h) is materially connected to the connecting surface (3f), preferably welded.

13. The battery module (1) according to the preceding claim, wherein the footing of the contact spring (3b) is covered by the protruding planar segment (3d) of the spring tongue (3c) of the contact spring (3b).

14. The battery module (1) according to any one of claims 12 or 13, wherein the footing of the contact spring (3b) has a through hole (3g).

15. Use of the battery module (1) according to any one of the preceding claims in a motor vehicle.

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