DE102013225340B4 - Battery module with a plurality of battery cells and battery system with at least one such battery module - Google Patents

Abstract

Battery module (1) with a plurality of battery cells (2), each of which has a first cell terminal (3) with at least one contacting section (5) and a second cell terminal (4) with at least one contacting section (5), the battery cells (2) are electrically interconnected by electrically connecting the contacting section (5) of a cell terminal (3, 4) of a battery cell (2) to the contacting section (5) of a cell terminal (3, 4) of a further battery cell (2) by means of a cell connector (7). is conductively connected, the connection of the contacting sections (5) to the respective cell connector (7) being a plug connection, the cell connectors (7) each having a first contacting opening and a second contacting opening, the contacting section (5) being inserted into the first contacting opening Cell terminals (3, 4) of a battery cell (2) is inserted in a force-fitting manner and the contacting section (5) of a cell terminal (3, 4) of a further battery cell (2) is inserted in a force-fitting manner into the second contacting opening and the first cell terminal (3) and the second The cell terminal (4) of a battery cell (2) of the battery module (1) is each designed as a contact lug, with the at least one contacting section (5) of the respective cell terminal (3, 4) being formed from the free end of the contact lug, at least those contacting sections ( 5), which are electrically conductively connected by means of a cell connector (7), face each other.

Description

The invention relates to a battery module with a plurality of battery cells, each of which has a first cell terminal with at least one contacting section and a second cell terminal with at least one contacting section, the battery cells being electrically connected to one another in that the contacting section of a cell terminal of a battery cell is connected by means of a cell connector is electrically conductively connected to the contacting section of a cell terminal of another battery cell.

The invention further relates to a battery system with at least one battery module.

State of the art

Battery modules, such as battery modules designed in particular as energy storage devices for providing the energy required for the operation of hybrid, plug-in hybrid or electric vehicles, usually comprise several battery cells, the battery cells each having at least one negative electrode and at least one positive electrode. The electrode arrangement can vary depending on the design of the battery cell. In particular, so-called cell stacks or cell rolls (Jelly Roll) are known as electrode arrangements. Due to the comparatively high energy density, lithium-ion cells in particular are used as battery cells. The battery cells are usually surrounded by a cell housing. Battery modules used in electric vehicles in particular have battery cells with a metallic cell housing, which protect the electrode arrangement from moisture and mechanical stress.

For electrically conductive contacting of the battery cells, the battery cells usually have two cell terminals, one cell terminal being electrically conductively connected to the negative electrode of the battery cell and the other cell terminal being electrically conductively connected to the positive electrode of the battery cell. Using so-called cell connectors, which serve as a contacting element and are often made of copper or aluminum, the battery cells are electrically connected to one another via the cell terminals to form a battery module.

When connecting the battery cells to form a battery module, the focus is on connecting the cell connectors to the cell terminals. Different types of connections are known for this purpose. In particular, the cell connectors and the cell terminals can be designed in such a way that they can be screwed together or the cell connectors can be screwed onto the cell terminals. The advantage here is that the connections can be detached again, so that individual battery cells can be easily replaced, for example. However, such screw connections also have various disadvantages. Applying too high a torque can damage the threads. Furthermore, a lot of time is required for screwing. In addition, a screw connection usually requires a high electrical contact resistance, which can increase further over time, for example due to vibrations and shocks that occur in particular when such battery cells are used in a vehicle.

As an alternative to screwing, an electrically conductive connection of battery cells can be produced by welding the cell connectors to the cell terminals of the battery cells. A welded connection advantageously has a low electrical contact resistance and enables a permanently stable connection between the cell connector and the cell terminal. However, when the cell connectors are welded to the cell terminals, it is not possible to detach the battery cells that are electrically connected using the welded connection from each other again without being destroyed. If a single battery cell is defective, it cannot be replaced individually, but rather the entire battery module must be replaced, which means that the costs are high if a battery cell is defective. There is also the further disadvantage that quality control of the weld seam is difficult or impossible. In addition, the laser welding systems preferred for welding are expensive.

Against this background, it is an object of the present invention to improve a battery module with a plurality of battery cells, in particular with regard to the electrical contacting of the cell terminals of the battery cells. In particular, a battery module should be provided with a detachable but permanently stable and low-resistance electrical connection of cell terminals, preferably using prismatic battery cells.

The state of the art in this regard is, for example, the publications US 2010/0 266 889 A1 , US 6,391,489 B1 , DE 10 2008 044 492 A1 , US 5,662,497 A or KR 10 2013 0 036 669 A .

Disclosure of the invention

To solve the problem, a battery module with a plurality of battery cells is used, which each having a first cell terminal with at least one contacting section and a second cell terminal with at least one contacting section, proposed, wherein the battery cells are electrically connected to one another by electrically conductively connecting the contacting section of a cell terminal of a battery cell to the contacting section of a cell terminal of a further battery cell by means of a cell connector is, wherein the connection of the contacting sections to the respective cell connector is a plug connection. Here, a non-positive connection is established by the plug connection between the cell connector and the respective contacting section. This means that there is no need for screwing or welding, which advantageously reduces the costs for producing the electrically conductive connection between battery cells. The plug connection is advantageously designed to be detachable. As a result, an electrically conductive connection between battery cells can advantageously be easily separated again by appropriately disassembling the cell connector and the contacting section. This advantageously simplifies the replacement of a defective battery cell from the battery module.

The at least one contacting section is a part of the respective cell terminal, with the at least one contacting section being manufactured in one piece with the respective cell terminal.

In particular, it is provided that the battery module according to the invention is designed at least as part of an energy storage device which provides the energy required for the operation of a hybrid, plug-in hybrid or electric vehicle. The battery cells of the battery module are preferably lithium-ion cells. The battery cells of the battery module according to the invention are preferably connected in series and/or parallel. In particular, according to an advantageous embodiment of the invention, it is provided that some battery cells of a battery module are electrically connected to one another in a conventional manner, in particular by welding a cell connector, with the battery cells connected in this way forming subunits, which are then connected to other subunits and/or battery cells are interconnected in a manner according to the invention by electrically conductively connecting the contacting section of a cell terminal of a subunit by means of a cell connector to the contacting section of a cell terminal of a further subunit or a battery cell, wherein the connection of the contacting sections to the cell connector is in each case a plug-in connection . Such a subunit essentially forms a battery cell in the sense of the present invention.

According to the invention, it is provided that the cell connectors each have a first contacting opening and a second contacting opening, the contacting section of a cell terminal of a battery cell being non-positively inserted into the first contacting opening and the contacting section of a cell terminal of a further battery cell being non-positively inserted into the second contacting opening. In this embodiment, the contacting sections of the cell terminals connected to one another in an electrically conductive manner form the male part of the plug connection and the cell connectors form the female part. Such a configuration advantageously promotes a one-piece design of the at least one contacting section with the respective cell terminal. This is because the respective contacting section can be designed in a structurally simple manner as an outward-facing contact pin. In particular, it is provided that the cell connector section having the contacting opening can be pushed onto the cell connector against the force of a mechanical spring, such that the contacting opening is pushed onto the cell connector and the overall length of the cell connector is thereby shortened. This advantageously further simplifies the production of the plug connection.

According to the invention, the first cell terminal and the second cell terminal of a battery cell of the battery module are each designed as a contact lug, with the at least one contacting section of the respective cell terminal being formed from the free end of the contact lug. A contact tab in the sense of the present invention is in particular a flat and comparatively thin contacting element. Such contacting elements or contact lugs are known in particular from so-called pouch cells. In the present invention, it is particularly provided that the cell terminals of prismatic battery cells, in which the electrode arrangement is surrounded by a metallic cell housing, a so-called hard case, are designed as such a contact element or as a contact lug. In particular, it is provided that the cell housing of the battery cells comprises two metal half-shells, which are arranged around the electrode arrangement in such a way that only the cell terminals designed as contact tabs protrude from the assembled half-shells. The half-shells can be connected to one another, in particular by welding, to form a prismatic cell housing. The cell terminals are each electrically insulated from the cell housing.

Preferably, the at least one contacting section of a cell terminal designed as a contact lug is angled by deformation, particularly preferably angled at right angles. This advantageously further simplifies the production of the plug connection of a contacting section with a cell connector. In order to form several contacting sections, it is in particular provided that the cell terminal terminates in several free ends, each free end representing a contacting section in the sense of the present invention. If the cell terminal is designed as a contact tab, it is in particular provided that two contacting sections are formed in that the cell terminal has an incision at its free end, preferably in the middle, the section of the cell terminal to the left of the incision forming a first contacting section and the section of the cell terminal to the right of the incision forms a second contacting section. Preferably, the first contacting section and the second contacting section are angled in opposite directions, particularly preferably at an angle of 90°.

According to the invention, it is provided that at least those contacting sections that are electrically conductively connected by means of a cell connector face each other. This advantageously further simplifies the production of the plug connection. In particular, the alignment of the contacting sections of the battery cells can determine how the battery cells are to be connected to one another, in that always those battery cells that are arranged next to one another and whose contacting sections face each other are electrically conductively connected to a cell connector.

In a further particularly preferred embodiment of the battery module according to the invention, the battery cells each have a prismatic cell housing from which the first cell terminal and the second cell terminal protrude, the contacting sections each being spaced apart from the cell housing by a cell terminal section parallel to the area of the cell housing from which the first cell terminal and the second cell terminal protrude, are aligned. This advantageously further simplifies the electrically conductive connection of battery cells arranged next to one another. Advantageously, the cell terminals are designed to be at least partially elastically restoring, so that producing the plug connection is even further simplified.

Preferably, the at least one contacting section of a cell terminal is formed by bending the free end of the respective cell terminal. In particular, it is provided that the contacting sections of the battery cells of the battery module are angled in such a way that contacting sections that are electrically conductively connected to one another face one another. The contacting sections preferably lie in one plane. This advantageously further improves the connectivity of the contacting sections.

A further advantageous embodiment of the battery module according to the invention provides that a number of battery cells are electrically connected in parallel, the cell terminals of these battery cells each having a first contacting section and a second contacting section, with a first further battery cell being connected via the first contacting section of a battery cell connected in parallel and above a second further battery cell is electrically conductively connected to the second contacting section. In particular, it is provided that the cell terminal of a battery cell of the battery module protrudes from the cell housing in a “T” shape, the “I” section being the cell terminal section through which the first and second contacting sections are each spaced from the cell housing. The “-” section forms the first contacting section and the second contacting section. Preferably, the contacting sections of battery cells arranged next to one another face each other. According to one embodiment variant, the first and second contacting sections of a cell terminal each point inwards and outwards and therefore not towards neighboring battery cells. In this embodiment variant, these cell terminals are contacted laterally by means of a cell connector, the cell connector being plugged onto the contacting sections by being brought laterally towards the respective cell terminal to be contacted.

A further advantageous embodiment of the battery module according to the invention provides that a number of battery cells are electrically connected in series, the cell terminals of these battery cells each having at least one contacting section, with a further battery cell being electrically conductively connected via the contacting section of a battery cell connected in series.

To solve the problem mentioned at the beginning, a battery system comprising at least one battery module with a plurality of battery cells is further proposed, the at least one battery module being a battery module according to the invention This battery module is. In particular, it is provided that the battery system has a plurality of battery modules, with the battery modules being connected to one another in parallel and/or in series. In particular, it is envisaged that the battery system is a battery system designed for use in hybrid, plug-in hybrid or electric vehicles. The battery system includes various system components, in particular at least one cooling device for temperature control of the battery cells and/or a battery management system for monitoring and controlling the battery modules.

• 1 in einer schematischen Darstellung ein Ausführungsbeispiel für ein erfindungsgemäßes Batteriemodul;
• 2 in einer schematischen Darstellung ein weiteres Ausführungsbeispiel für ein erfindungsgemäßes Batteriemodul;
• 3 in einer schematischen Darstellung ein weiteres Ausführungsbeispiel für ein erfindungsgemäßes Batteriemodul;
• 4 in einer schematischen Darstellung ein weiteres Ausführungsbeispiel für ein erfindungsgemäßes Batteriemodul;
• 5 in einer schematischen Darstellung eine perspektivische Ansicht eines Ausführungsbeispiels für eine Batteriezelle eines erfindungsgemäßen Batteriemoduls;
• 6 in einer schematischen Darstellung ein weiteres Ausführungsbeispiel für eine Batteriezelle eines erfindungsgemäßen Batteriemoduls; und
• 7 in einer schematischen Darstellung ein Ausführungsbeispiel für eine Elektrodenanordnung mit Zellterminals einer Batteriezelle eines erfindungsgemäßen Batteriemoduls.

Further advantageous details, features and design details of the invention are explained in more detail in connection with the exemplary embodiments shown in the figures. This shows:

• 1 in a schematic representation an embodiment of a battery module according to the invention;
• 2 in a schematic representation a further embodiment of a battery module according to the invention;
• 3 in a schematic representation a further embodiment of a battery module according to the invention;
• 4 in a schematic representation a further embodiment of a battery module according to the invention;
• 5 in a schematic representation a perspective view of an exemplary embodiment of a battery cell of a battery module according to the invention;
• 6 in a schematic representation a further embodiment of a battery cell of a battery module according to the invention; and
• 7 in a schematic representation an embodiment of an electrode arrangement with cell terminals of a battery cell of a battery module according to the invention.

1 until 4 each show exemplary embodiments for a battery module 1 according to the invention. It is provided that a battery cell 2 each has two cell terminals 3, 4, as for example in 5 shown. For reasons of better overview, in 1 until 4 Only the cell terminals of the battery cells 2 in the foreground are shown. The cell terminals of the battery cells 2 in the background are not explicitly shown. The battery cells 2 are each arranged next to one another and electrically connected to one another.

This in 1 Battery module 1 shown as an example includes four prismatic battery cells 2, each of which is surrounded by a metallic housing, a so-called hard case. The battery cells 2 each have a first cell terminal 3 with a contacting section 5 and a second cell terminal 4 with a contacting section 5. In particular, it is provided that the first cell terminals 3 are made of copper and the second cell terminals 4 are made of aluminum. Those contacting sections 5 that are electrically conductively connected by means of a cell connector 7, i.e. a contacting section 5 of a first cell terminal 3 and a contacting section 5 of a second cell terminal 4, face each other.

The contacting sections 5 are each spaced from the cell housing of the respective battery cell 2 by a cell terminal section and aligned parallel to the area of the cell housing from which the respective cell terminals 3, 4 protrude. In particular, it is provided that a contacting section 5 and a cell terminal 3 or a cell terminal 4, differently than in 1 shown, are formed in one piece and the contacting sections 5 are each formed by bending the free end of the respective cell terminal 3, 4. The cell terminals 3, 4 of a battery cell 2 are preferably designed as a contact lug.

The battery cells 2 of the battery module 1 are in the in 1 illustrated embodiment connected to a so-called 4s1 p configuration, that is, that four battery cells 2 are electrically connected in series. The connection of the battery cells 2 is such that the contacting section 5 of a first cell terminal 3 is electrically conductively connected to the contacting section 5 of a second cell terminal 4 by means of a cell connector 7, the connection of the contacting sections 5 to the cell connector 7 being a plug connection.

The cell connectors 7 point in the in 1 illustrated embodiment each has a first contact opening (in 1 not explicitly shown) and a second contact opening (in 1 not explicitly shown). The contacting section 5 of the first cell terminal 3 of a battery cell 2 is inserted in a force-fitting manner into the first contacting opening. The contacting section 5 of the second cell terminal 4 of a further battery cell 2 is inserted in a force-fitting manner into the second contacting opening.

At the in 2 In the illustrated embodiment of a battery module 1 according to the invention, the battery cells 2 are connected to one another in a 3s2p configuration. This means that a series connection consists of two connected in parallel Battery cells 2 are present. There are in 2 The two battery cells 2 arranged next to each other are connected in parallel, in which the first cell terminals 3 can be seen in the foreground, and the two battery cells 2 arranged next to each other, in which two cell terminals 4 can be seen in the foreground.

Some of the battery cells 2 have cell terminals 3, 4 with a first contacting section 5 and a second contacting section 6 (in 2 shown in the battery cells 2, which are arranged in the second and third positions when viewed from left to right), the corresponding cell terminals 3, 4 together with their contacting sections 5, 6 being designed in a “T” shape. For example, in 2 battery cell 2 arranged in the second position from the left, the first contacting section 5 of the cell terminal 3 is electrically conductively connected by means of a cell connector 7 to the first contacting section 5 of the cell terminal 3 of the battery cell 2 arranged in the first position from the left (part of the parallel circuit) and the second contacting section 6 of the first cell terminal 3 is electrically conductively connected by means of a further cell connector 7 to the first contacting section 5 of the second cell terminal 4 of the battery cell 2 arranged in the third position from the left (part of the series connection). The contacting sections 5, 6 of the different battery cells 2 face each other.

Next is in 2 based on the battery cells 2, which are arranged in the fifth and sixth position from the left, it is shown by way of example that at least some of the electrically conductive connections between battery cells 2 of a battery module 1 according to the invention cannot be implemented as a plug connection, but rather, as in 2 shown as connection 14, which is produced by means of an enforcement method.

In particular, the contacting sections 5, 6 of the battery cells 2 can have different lengths, in particular depending on the planned interconnection of the battery cells 2.

At the in 3 and 4 In each illustrated embodiment of a battery system 1 according to the invention, some battery cells 2 are electrically conductively connected in pairs to form subunits, for example the ones in 3 and 4 Battery cells arranged in the first and second positions from the left 2nd in 3 In these battery cells, the cell terminals 3 are conductively connected to one another by a cell connector 8, the cell connector 8 being welded to the cell terminals 3. The cell connector 8 is preferably made of the same material as the cell terminals electrically conductively connected by it, in particular aluminum or copper. In 4 the electrically conductive connections 14 between the cell terminals 3 and between the cell terminals 4 are produced by means of a clinching process, preferably by means of clinching or toxing.

The cell terminals 3, 4 of these subunits each have a contacting section 5, via which the subunits are connected to one another in an electrically conductive manner as battery cells by means of a cell connector 7. The connection of a contacting section 5 to the cell connector 7 is implemented as a plug connection. Advantageously, these subunits can be easily replaced by loosening the plug connection made by means of the respective cell connector 7, especially in the event of a defect in such a subunit.

5 shows a particularly preferred embodiment of a battery cell 2 for use in a battery module according to the invention, in which battery cells of the battery module are electrically connected in series. The electrode arrangement (in 5 not explicitly shown) of the battery cell 2 surrounded by a metallic cell housing 9. The cell housing is formed from a first half-shell 10 and a second half-shell 11, which are welded together. The cell terminals 3, 4 of the battery cell 2, which are electrically conductively connected to the negative electrode or the positive electrode of the battery cell 2, are each designed as a contact tab. The cell terminals 3, 4 protrude from the cell housing 9 in an electrically insulated manner against the cell housing 9 and each have a contacting section 5. This is essentially angled at right angles by reshaping the free end of the cell terminal 3 or the cell terminal 4, so that the respective contacting section 5 is aligned parallel to the area of the cell housing 9 from which the first cell terminal 3 and the second cell terminal 4 protrude. The contacting section 5 of the first cell terminal 3 points in the opposite direction as the contacting section 5 of the second cell terminal 4. This is particularly advantageous since, in such a configuration, the contacting section 5 of the first cell terminal 3 has an in 5 The battery cell to be arranged in front of the battery cell 2 can be easily contacted and by means of the contacting section 5 of the second cell terminal 4 an in 5 Battery cell to be arranged behind the battery cell 2 can be easily contacted. The contacting takes place by means of a plug connection realized by a cell connector having contact openings.

6 shows a further exemplary embodiment of a battery cell 2 for use in a battery module according to the invention, with the electrode arrangement 12 of the battery cell 2 in the housing 9 being shown schematically. It is envisaged that the electrode arrangement 12 is designed as a cell stack, as is particularly known from a pouch cell. Unlike a pouch cell, the electrode arrangement 12 is arranged in a metallic prismatic cell housing 9. The electrode arrangement 12 is contacted by means of a first cell terminal 3 and a second cell terminal 4, each of which is designed as a contact tab, as is known from a pouch cell. This advantageously enables a simple formation of contacting sections, which, thanks to the flexibility of the cell terminals 3, 4, can be easily electrically conductively connected to other battery cells by plugging them together using a cell connector designed as a coupling.

At the in 7 In the further exemplary embodiment of a battery cell 2 shown for use in a battery module according to the invention, the electrode arrangement 12 is designed as a cell roll (“jelly roll”). Such an electrode arrangement is known from prismatic battery cells. At the in 7 In the exemplary embodiment shown, the cell terminals 3, 4 are designed as a contact tab, as in a pouch cell. The first cell terminal 3 is electrically insulated from the second cell terminal 4 of the battery cell 2 by means of an insulating element 13. In particular, it is provided that the battery cell 2 is in a cell housing, as in connection with 5 explained, is arranged. The free ends of the cell terminals 3, 4 designed as contact lugs are used according to the invention as a contacting section for producing an electrically conductive plug connection by means of a cell connector designed accordingly as a quick connector, in particular after previous forming, in particular by bending. The cell connector advantageously has corresponding receptacles for the non-positive connection of the contacting sections to the cell connector.

The exemplary embodiments shown in the figures and explained in connection with them serve to explain the invention and are not restrictive of it.

Claims (6)

Battery module (1) with a plurality of battery cells (2), each of which has a first cell terminal (3) with at least one contacting section (5) and a second cell terminal (4) with at least one contacting section (5), the battery cells (2) are electrically interconnected by electrically connecting the contacting section (5) of a cell terminal (3, 4) of a battery cell (2) to the contacting section (5) of a cell terminal (3, 4) of a further battery cell (2) by means of a cell connector (7). is conductively connected, the connection of the contacting sections (5) to the respective cell connector (7) being a plug connection, the cell connectors (7) each having a first contacting opening and a second contacting opening, the contacting section (5) being inserted into the first contacting opening Cell terminals (3, 4) of a battery cell (2) is inserted in a force-fitting manner and the contacting section (5) of a cell terminal (3, 4) of a further battery cell (2) is inserted in a force-fitting manner into the second contacting opening and the first cell terminal (3) and the second The cell terminal (4) of a battery cell (2) of the battery module (1) is each designed as a contact lug, with the at least one contacting section (5) of the respective cell terminal (3, 4) being formed from the free end of the contact lug, at least those contacting sections ( 5), which are electrically conductively connected by means of a cell connector (7), face each other. Battery module (1) according to the preceding claim, characterized in that the battery cells (2) each have a prismatic cell housing (9) from which the first cell terminal (3) and the second cell terminal (4) protrude, the contacting sections (5) respectively by a cell terminal section spaced from the cell housing (9) and aligned parallel to the area of the cell housing (9) from which the first cell terminal (3) and the second cell terminal (4) protrude. Battery module (1) according to one of the preceding claims, characterized in that the at least one contacting section (5) of a cell terminal (3, 4) is formed by bending the free end of the respective cell terminal (3, 4). Battery module (1) according to one of the preceding claims, characterized in that a number of battery cells (2) are electrically connected in parallel, the cell terminals (3, 4) of these battery cells (2) each having a first contacting section (5) and a second contacting section (6), wherein a first further battery cell (2) is electrically conductively connected via the first contacting section (5) of a parallel-connected battery cell (2) and a second further battery cell (2) is electrically conductively connected via the second contacting section (6). Battery module (1) according to one of the preceding claims, characterized in that a number of battery cells (2) are electrically connected in series, the cell terminals (3, 4) of these battery cells (2) each having at least one contacting section (5), whereby A further battery cell (2) is electrically conductively connected via the contacting section (5) of a battery cell (2) connected in series. Battery system comprising at least one battery module (1) with a plurality of battery cells (2), characterized in that the at least one battery module (1) is a battery module according to one of Claims 1 until 5 is.

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