DE102018211244A1 - battery cell - Google Patents

Abstract

The invention relates to a battery cell (2) comprising a cell housing in which an electrode unit is arranged, the electrode unit having an anode electrically connected to a negative terminal and a cathode electrically connected to a positive terminal, the cell housing comprising a first housing part (61 ) and a second housing part, and wherein an insulation unit (80) is provided in which the housing parts (61) are held in a form-fitting manner. The first housing part (61) has a base section (71), an intermediate section (72) adjoining the base section (71), which runs inclined with respect to the base section (71), and an end section on the intermediate section (72) (73), which is inclined with respect to the intermediate section (72).

Description

The invention relates to a battery cell, comprising a cell housing in which an electrode unit is arranged, the electrode unit having an anode electrically connected to a negative terminal and a cathode electrically connected to a positive terminal. The cell housing has a first housing part and a second housing part, and an insulation unit is provided in which the housing parts are held in a form-fitting manner.

State of the art

Electrical energy can be stored using batteries. Batteries convert chemical reaction energy into electrical energy. Lithium-ion battery cells are used in particular in an accumulator. These are characterized, among other things, by high energy densities, thermal stability and extremely low self-discharge. Lithium-ion battery cells have a positive electrode, which is also called a cathode, and a negative electrode, which is also called an anode. A battery cell also has a cell housing, which consists for example of aluminum. The cell housing is, for example, prismatic, in particular cuboid, or also circular cylindrical. Other designs for cell housings are also known.

The two electrodes of the electrode unit are electrically connected to poles of the battery cell, which are also referred to as terminals. The terminals of the battery cell can be attached to the cell housing and electrically isolated from the cell housing. However, it is also conceivable for the cell housing to have a first housing part which forms the negative terminal and a second housing part which forms the positive terminal, the two housing parts being electrically insulated from one another.

In order to safely degas the battery cell within the housing in the event of a fault, for example a short circuit, it is known, among other things, to provide predetermined breaking points or rupture disks on the housing of the battery cell.

The document DE 10 2011 078 301 A1 discloses a battery cell that includes a housing into which a check valve is inserted. The check valve comprises a spring element and a contact element which is fixed to the housing. The spring element is designed, for example, as a spiral spring. The contact element is glued to the housing, for example. In the event of overpressure within the battery cell, the check valve opens, the spring element being deformed against its restoring force.

The document DE 10 2014 019 075 A1 discloses a battery cell with a housing film which comprises a predetermined opening point. In this case, a film separating element is provided, which deforms in the event of overpressure within the battery cell and thereby cuts through the housing film of the battery cell and thus opens the target opening point.

The document DE 10 2014 006 807 A1 discloses a battery system with a plurality of battery cells, each having a cell venting device. The cell venting devices open at a predetermined internal pressure within the battery cells. Said cell venting devices are designed, for example, as local weakenings of the cell housing, in particular in the form of a predetermined breaking point.

The document DE 10 2012 221 753 A1 discloses a battery with a housing. The housing has a pressure release device, which is designed, for example, as a pressure relief valve. Likewise, the housing can be designed to be mechanically weakened locally, so that the housing yields to excess pressure at a defined location, as a result of which gas can escape from the housing.

Disclosure of the invention

A battery cell is proposed which comprises a cell housing. An electrode unit is arranged in the cell housing, the electrode unit has an anode electrically connected to a negative terminal and a cathode electrically connected to a positive terminal. The cell housing has a first housing part and a second housing part, an insulation unit being provided in which the housing parts are held in a form-fitting manner.

According to the invention, the first housing part has a base section, an intermediate section adjoining the base section, which runs inclined with respect to the base section. The intermediate section is adjoined by an end section which is inclined with respect to the intermediate section.

The base section is preferably at least approximately flat. The end section runs, for example, at least approximately parallel to the base section.

In the event of a fault within the cell housing of the battery cell, for example a short circuit in the electrode unit, overpressure arises within the cell housing due to the development of heat. By designing the In this case, the battery cell deforms the first housing part. This deformation creates a relatively large vent opening. Through this vent, the battery cell can be degassed relatively quickly and safely in the event of an internal fault.

According to a preferred embodiment of the invention, the intermediate section of the first housing part forms an angle with the base section between 45 ° and 135 °. The intermediate section begins at the base section and runs towards the second housing part. In particular, the intermediate section can run at right angles to the base section.

The end section preferably forms an angle between 45 ° and 135 ° with the intermediate section. In particular, the end section can run at right angles to the intermediate section.

According to an advantageous development of the invention, the base section of the first housing part comprises a weak point, which enables the base section to bend around the weak point. The weak point is, for example, in the form of a material weakening of the base section, in particular in the form of an embossing or in the form of material removal by means of a laser. In the event of an internal error, the base section then bends in particular around the said vulnerability.

The weak point of the base section is preferably designed and arranged in such a way that when the base section bends around the weak point, the intermediate section is moved and / or deformed. In particular, the weak point is located relatively close to the intermediate section.

The weak point of the base section is preferably also designed and arranged in such a way that when the base section bends around the weak point, the end section moves and / or is deformed.

The insulation unit of the battery cell advantageously insulates the housing parts from one another electrically. For this purpose, the insulation unit is made of an electrically non-conductive material, in particular plastic. The insulation unit can be constructed in several parts, preferably all parts of the insulation unit being made of an electrically non-conductive material.

According to an advantageous embodiment of the invention, the insulation unit of the battery cell comprises a holder and an insert element. The insert element electrically isolates the first housing part from the negative terminal and / or from the positive terminal. The holder is made of an electrically insulating material and is used in particular to hold the first housing part and the second housing part and the electrode unit in a form-fitting manner. In addition, the holder isolates the negative terminal and the positive terminal from each other and from the second housing part. The holder also serves for the electrical insulation of the electrode unit.

According to a preferred development of the invention, the end section of the first housing part is glued to the insulation unit in at least one adhesive area. The end section can, for example, be glued to the holder and / or to an insert element. In the event of overpressure within the cell housing, the adhesive area can tear open relatively easily and thus further enlarge the degassing opening.

According to a possible embodiment of the invention, the battery cell is designed as a full contact cell. A fully contact cell does not have separate terminals, but rather the generally flat housing parts represent the terminals. In the present case, for example, the first housing part forms the negative terminal and the second housing part forms the positive terminal. Alternatively, the first housing part forms the positive terminal and the second housing part forms the negative terminal.

A battery cell according to the invention is advantageously used in an electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV), in a stationary battery, in particular for network stabilization in households, in a battery in a marine application, for example in shipbuilding or in jet skis, or in a battery in an aeronautical application, in particular in aircraft construction. Other applications are also conceivable.

Advantages of the invention

A battery cell designed according to the invention has a safety valve which opens in the event of a fault within the cell housing of the battery cell, for example a short circuit in the electrode unit. Such an error creates an overpressure within the cell housing due to the development of heat, which can escape through the opened safety valve. The safety valve is implemented through a relatively large degassing opening, which is generated within the cell housing in the event of an excess pressure. In the event of an internal fault, the battery cell can be degassed relatively quickly and safely through said degassing opening. The function of the Safety valve is primarily formed by the geometric configuration of the cell housing, in particular the first housing part. The function of the safety valve can advantageously be improved by further features, in particular by an additional weak point in the first housing part and by a connection of the first housing part by means of an adhesive area. In the event of overpressure within the cell housing, the first housing part can then bend, in particular, around said weak point. Furthermore, the adhesive area can tear open relatively easily and thus further enlarge the resulting degassing opening. The configuration of the battery cell according to the invention can also be used with a full contact cell.

A relatively small weakening of material in the form of the weak point creates a relatively large vent opening when the housing is deformed. It is possible to position the weak point on the optimal side of the electrode unit, in particular on the end face at which the contact tabs emerge. The relatively small two-dimensional size of the safety valve makes it possible to easily connect add-on parts, which must under no circumstances come into contact with hot gas, for example a quick discharge device, to the battery cell. An undercut in the insulation unit, in particular the holder, is also not necessary. A simple holder is possible for fully contact cells. To produce the adhesive area, an adhesive can simply be applied to the insulation unit.

Brief description of the drawings

Embodiments of the invention are explained in more detail with reference to the drawings and the description below.

• 1 eine schematische Schnittdarstellung einer Batteriezelle,
• 2 eine perspektivische Darstellung einer Batteriezelle,
• 3 eine perspektivische Darstellung eines Teilbereichs der Batteriezelle aus 2,
• 4 eine Schnittdarstellung eines Teilbereichs der Batteriezelle aus 2 und,
• 5 eine Schnittdarstellung eines Teilbereichs der Batteriezelle aus 2 im Fehlerfall.

Show it:

• 1 1 shows a schematic sectional illustration of a battery cell,
• 2 a perspective view of a battery cell,
• 3 a perspective view of a portion of the battery cell 2 .
• 4 a sectional view of a portion of the battery cell 2 and,
• 5 a sectional view of a portion of the battery cell 2 in case of an error.

Embodiments of the invention

In the following description of the embodiments of the invention, the same or similar elements are denoted by the same reference symbols, with a repeated description of these elements being dispensed with in individual cases. The figures represent the subject matter of the invention only schematically.

1 shows a schematic sectional view of a battery cell 2 , The battery cell 2 comprises a cell housing 3 , which is electrically conductive in the present case. The cell housing 3 has a first housing part 61 and a second housing part 62 which by an insulation unit 80

are isolated from each other. The housing parts 61 . 62 are made of a metal, such as aluminum.

The battery cell 2 includes a negative terminal 11 and a positive terminal 12 , Via the terminals 11 . 12 can one from the battery cell 2 provided voltage can be tapped. Furthermore, the battery cell 2 through the terminals 11 . 12 also be loaded.

In the present case, the terminals protrude 11 . 12 from the cell housing 3 out and are through the isolation unit 80 from the housing parts 61 . 62 , and from each other, electrically isolated. But it is also conceivable that the first housing part 61 the negative terminal 11 forms, and that the second housing part 62 the positive terminal 12 forms, or that the first housing part 61 the positive terminal 12 forms, and that the second housing part 62 the negative terminal 11 forms.

Inside the cell housing 3 the battery cell 2 is an electrode unit 10 arranged which two electrodes, namely an anode 21 and a cathode 22 , having. The electrode unit 10 is designed, for example, as an electrode coil, and the anode 21 and the cathode 22 are each foil-like and with the interposition of a separator 18 wound on the electrode coil. It is also conceivable that the electrode unit 10 is designed as an electrode stack, layers of the anode 21 and layers of the cathode 22 with one layer of the separator in between 18 are stacked on top of each other.

The anode 21 comprises an anodic active material 41 , which is designed like a film. The anode 21 further includes a current arrester 31 . which is also film-like. The anodic active material 41 and the current arrester 31 the anode 21 are laid flat and connected to each other. So is the anode too 21 formed like a film.

The cathode 22 comprises a cathodic active material 42 , which is designed like a film. The cathode 22 further includes a current arrester 32 , which is also film-like. The cathodic active material 42 and the current arrester 32 the cathode 22 are laid flat and connected to each other. So is the cathode too 22 formed like a film.

The current arrester 31 the anode 21 is electrically conductive and made of a metal, for example copper. From the current arrester 31 the anode 21 protrude anode contact lugs, which are electrically connected to the negative terminal 11 the battery cell 2 are connected. So the anode 21 electrically with the negative terminal 11 connected.

The current arrester 32 the cathode 22 is electrically conductive and made of a metal, such as aluminum. From the current arrester 32 the cathode 22 protruding cathode contact lugs, which are electrically connected to the positive terminal 12 the battery cell 2 are connected. So the cathode 22 electrically with the positive terminal 12 connected.

2 shows a perspective view of a battery cell 2 , The isolation unit 80 the battery cell 2 includes a rotating holder 83 which, for example, has an H-shaped cross section. The isolation unit 80 further comprises an insert element 85 which is on one side of the holder 83 rests. The keeper 83 and the insert element 85 are, for example, injection molded from plastic.

In the holder 83 the isolation unit 80 are the first housing part 61 and the second housing part 62 held positively. Furthermore, the electrode unit is not visible here 10 in the holder 83 the isolation unit 80 held. The keeper 83 the isolation unit 80 further isolates the negative terminal 11 and the positive terminal 12 from each other and from which the second housing part, not visible here 62 electric. The insert element 85 the isolation unit 80 isolates the first housing part 61 from the negative terminal 11 and from the positive terminal 12 electric.

In the holder 83 the isolation unit 80 is also a filler opening 65 intended. The filling opening 65 is used in particular to fill a liquid electrolyte into the cell housing 3 the battery cell 2 , After filling the liquid electrolyte, the filling opening 65 usually tightly closed.

3 a perspective view of a portion of the battery cell 2 out 2 , Here is the first housing part 61 removed and those in the holder 83 the isolation unit 80 held electrode unit 10 is visible. From the electrode unit 10 protrude the anode contact tabs of the anode 21 gone and are with the negative terminal 11 connected. From the electrode unit 10 also protrude the cathode contact tabs of the cathode 22 gone and are with the positive terminal 12 connected.

4 shows a sectional view of a portion of the battery cell 2 out 2 , The section shown includes the holder 83 , the insert element 85 and the first housing part 61 , The electrode unit 10 as well as the terminals 11 . 12 are not shown.

The first housing part 61 has a flat and flat basic section 71 on which parallel to the second housing part, not shown here 62 runs. To the basic section 71 concludes an intermediate section 72 on. The intermediate section 72 of the first housing part 61 runs inclined with respect to the base section 71 , The intermediate section is present, but not mandatory 72 approximately perpendicular to the base section 71 ,

At the intermediate section 72 of the first housing part 61 closes an end section 73 on. The end section 73 of the first housing part 61 runs at least approximately parallel to the base section 71 , The end section 73 thus runs inclined, in this case approximately at right angles, to the intermediate section 72 ,

The end section 73 of the first housing part 61 is with the isolation unit 80 , in the present case with the insert element 85 , in an adhesive area 88 bonded. The adhesive area 88 is designed in such a way that in the event of overpressure inside the cell housing 3 the adhesive area 88 can tear open relatively easily.

In the basic section 71 of the first housing part 61 is a vulnerability 75 brought in. The weak point 75 is in the form of material weakening of the base section 71 executed, for example in the form of an embossing or in the form of material removal by means of a laser. The weak point 75 allows the base section to bend 71 around the vulnerability 75 in the event of overpressure inside the cell housing 3 ,

5 shows a sectional view of a portion of the battery cell 2 out 2 in case of an error. The same sub-area is shown that also in 4 is shown. As a result of overpressure within the cell housing 3 has a deformation of the first housing part 61 occurred. This deformation of the first housing part 61 is a relatively large degassing opening through which degassing the battery cell 2 is possible.

The basic section 71 of the first housing part 61 has a bend around the vulnerability 75 Experienced. One between the vulnerability 75 and the intermediate section 72 area of the basic section 71 is deformed and is now inclined to the rest of the base section 71 , In particular, it protrudes between the vulnerability 75 and the intermediate section 72 area of the basic section 71 from the isolation unit 80 path.

By said deformation of the base section 71 the intermediate section is shifted 72 of the first housing part 61 , also from the isolation unit 80 path. The adhesive area also has 88 largely resolved, and the end section 73 of the first housing part 61 has changed from the insert element 85 the isolation unit 80 solved.

In the illustration shown here is the basic section 71 opposite end region of the end section 73 still in contact with the insert element 85 the isolation unit 80 , With a further increase in the overpressure within the cell housing 3 will also be this end portion of the end section 73 away from the isolation unit 80 remove and enlarge the vent opening further.

The invention is not restricted to the exemplary embodiments described here and the aspects emphasized therein. Rather, a large number of modifications are possible within the scope specified by the claims, which lie within the framework of professional action.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011078301 A1 [0005]
• DE 102014019075 A1 [0006]
• DE 102014006807 A1 [0007]
• DE 102012221753 A1 [0008]

Claims (10)

Battery cell (2), comprising a cell housing (3) in which an electrode unit (10) is arranged, the electrode unit (10) having an anode (21) electrically connected to a negative terminal (11) and one with a positive terminal (12 ) has an electrically connected cathode (22), the cell housing (3) having a first housing part (61) and a second housing part (62), and an insulation unit (80) being provided in which the housing parts (61, 62) are form-fitting are held, characterized in that the first housing part (61) has a base section (71), the base section (71) being adjoined by an intermediate section (72) which is inclined with respect to the base section (71), and wherein the Intermediate section (72) connects an end section (73) which runs inclined with respect to the intermediate section (72). Battery cell (2) after Claim 1 , characterized in that the intermediate section (72) forms an angle with the base section (71) between 45 ° and 135 °. Battery cell (2) according to one of the preceding claims, characterized in that the base section (71) comprises a weak point (75) which enables the base section (71) to bend around the weak point (75). Battery cell (2) after Claim 3 , characterized in that the weak point (75) is designed and arranged in such a way that when the base section (71) bends around the weak point (75), the intermediate section (72) moves and / or deforms. Battery cell (2) according to one of the Claims 3 to 4 , characterized in that the weak point (75) is designed and arranged such that when the base section (71) bends around the weak point (75) there is movement and / or deformation of the end section (73). Battery cell (2) according to one of the preceding claims, characterized in that the insulation unit (80) electrically isolates the housing parts (61, 62) from one another. Battery cell (2) according to one of the preceding claims, characterized in that the insulation unit (80) has a holder (83) and an insert element (85) which separates the first housing part (61) from the negative terminal (11) and / or from the positive terminal (12) electrically isolated. Battery cell (2) according to one of the preceding claims, characterized in that the end section (73) is glued to the insulation unit (80) in at least one adhesive region (88). Battery cell (2) according to one of the preceding claims, characterized in that the first housing part (61) forms the negative terminal (11) and the second housing part (62) forms the positive terminal (12), or in that the first housing part (61 ) forms the positive terminal (12), and the second housing part (62) forms the negative terminal (11). Use of a battery cell (2) according to one of the preceding claims in an electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV), in a stationary battery, in a battery in a marine application or in a battery in an aeronautical application.

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