WO2015180912A1

WO2015180912A1 - Making cells safe that have flat cell terminal leads

Info

Publication number: WO2015180912A1
Application number: PCT/EP2015/059091
Authority: WO
Inventors: Markus Kohlberger; Dirk Liepold
Original assignee: Robert Bosch Gmbh
Priority date: 2014-05-27
Filing date: 2015-04-27
Publication date: 2015-12-03
Also published as: DE102014210137A1

Abstract

The invention relates to a battery cell (10) comprising a seal (14), a first terminal lead (18) made of a material (30) having a first specific electrical conductivity, and a second terminal lead (20) made of a material (32) having a second specific electrical conductivity which is greater than the first specific electrical conductivity. A ratio of the cross-sections (58, 60) of the terminal leads (18, 20) is reciprocal to the ratio of the specific electrical conductivities of the materials (30, 32) of the terminal leads (18, 20).

Description

Description title

Cell protection in flat cell arresters state of the art

The invention relates to a battery cell, with a seal over which a first Abieiter of a material having a first electrical conductivity and a second Abieiter of a material having a second electrical conductivity protrude.

In the case of lithium-ion battery cells, in particular in the case of lithium-ion pouch cells, active electrode material is located in a foil-like housing which is sealed by a seal. By sealing the two Abieiter such battery cells are led to the outside. The two arresters are usually made of a foil strip with a respective material thickness of 50 mm to 500 mm. In this case, a Abieiter is usually made of an aluminum-containing alloy and the other Abieiter made of a copper-containing alloy. Alternatively, it is possible to have a combination between an Abieiter made of an aluminum alloy and another Abieiter from a nickel alloy

use. To protect against corrosion, the two Abieiter one

Containing aluminum alloy or a copper alloy, often plated with nickel.

The width of the strip-shaped Abieiter depends on the

required current flow and is used in the consumer sector

Battery cells in the order of 3 mm to 6 mm. For battery cells, however, which are suitable for applications in the automotive sector, the width of the strip-shaped Abieiter is typically between 50 mm to 70 mm. In exceptional cases, widths of up to 100 mm can be carried out, the two Abieiter usually have the same widths. Own metals different specific electrical conductivities given below:

Nickel 13.9 ^■ 10 ⁶ A / (V m),

Aluminum 37.7 ^· 10 ⁶ A / (V m),

Copper 59, 1 ^· 10 ⁶ A / (V m).

Due to the different specific electrical conductivities arises at that Abieiter, which has the lower specific conductivity, at a high current flow, for example, when a short circuit occurs more heat and this Abieiter thus melts through. Due to this, the current flow is interrupted. The melting of the Abieiters usually takes place very close to the edge of the seals of such battery cells. When melting, the seal can be damaged, as a result, the battery cell can be leaking. The resulting chemical reactions between the penetrating atmospheric oxygen and the electrolyte stored in the battery cell, as well as the material of the electrode ensemble, can be hazardous to humans and the environment.

Even with a nearly undamaged seal after the

By melting a Abieiters a subsequent discharge of the respective battery cells is not possible because due to the lack of supernatant at

molten Abieiter no contacting of the same is more possible. This means that for disposal, or recycling, a

accordingly prepared battery cell, this in the presence of a

Residual voltage must be opened, which can also be associated with hazards.

DE 103 27 203 A1 relates to an electrochemical storage battery. The electrochemical storage battery has cells filled with an electrolyte, and current sinking elements electrically connected to the cells. The Stromabieiterelemente are constructed multi-layered, wherein a first, directly connected to a cell contact layer of a Stromabieiterelementes consists of a first against the influence of the electrolyte corrosion-resistant, conductive material. And a second line layer adjoining the contact layer Conductor element consists of a second material having an electrical conductivity which is greater than the electrical conductivity of the first material.

Presentation of the invention

According to the invention, a battery cell is proposed with a seal, over which a first Abieiter of a material having a first electrical conductivity and a second Abieiter of a material having a second electrical conductivity protrude, wherein the second electrical conductivity, the first electrical

Conductivity exceeds and a ratio of the cross sections of Abieiter correspond to a reciprocal ratio of the electrical conductivities of the materials of Abieiter.

Such an optimization of the Abieiter the different electrical conductivities of the two materials used as Ableitermaterialien can be compensated. The introduced cross-sectional reduction on that of the Abieiter, which is made of a material having a lower specific conductivity, allows it to melt through at a high current flow and ensures its interruption.

In an advantageous development of the concept underlying the invention, the two Abieiter are formed in identical supernatants. The two Abieiter, which are outside the sealing of the preferred trained as a pouch cell battery cell, are of identical length.

In the case of the battery cell proposed according to the invention, that of the two conductors formed from the material having the first specific conductivity has a reduced cross-section outside the battery cell. The reduced

Cross section of the first Abieiters is reduced by at least 5%, preferably between 20% and 30%, based on the remaining cross section of the first Abieiters.

In addition, the reduced cross-section in the first Abieiter is in one

Minimum distance, relative to a sealing edge of the seal of the battery cell, which is in particular a pouch cell. The minimum distance is a few millimeters, preferably 2 mm and 3 mm, so that after a melt through the first Abieiters on occurrence of excessive current flow, a secure electrical contact of the fused Ableiterstumpfes is possible.

In the case of the battery cell proposed according to the invention, it is possible to manufacture the reduced cross section in a multiplicity of possible design variants. Thus, the reduced cross-section in the first Abieiter by at least one lateral taper, for example, in a one or both sides formed notch, be formed. In order to reduce the notch effect, care must be taken to maintain the mechanical strength of the first Abieiters the notches in

Kerbgrund rounded are formed.

In addition, it is possible to form the reduced cross section in the first Abieiter by one or more holes. A bore may be formed in a first diameter, a plurality of holes are formed, they may, for example, horizontally next to each other, be formed over the width of the first Abieiters extending to a lesser extent, so that the desired cross-sectional weakening due to the reduced cross-section in the first Abieiter established. Alternatively, it is possible to make one or more slits in the material of the first Abieiters. This may, for example, be a horizontal slit extending substantially in the horizontal direction, which leads to the desired weakening, ie. H. the formation of the reduced cross section in the first Abieiter leads; In addition, there is the possibility of at least one vertical slit in the tongue-shaped first Abieiter

train.

Furthermore, the reduced cross section in the first Abieiter can be formed by a one or two sides formed embossing in the first Abieiter. The reduced cross-section is established either by embossing on both sides of the first abieiter or, in the case of the formation of a one-sided embossing, by the depth of the embossing mark.

The invention also relates to a use of the battery cell, in particular a pouch cell, in a traction battery of a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV) or an electric vehicle (EV). Advantages of the invention

By the proposed solution according to the invention with regard to the formation of the cross sections of the two at the trained as a pouch cell battery cell

Abieiter performed, the different electrical conductivity of the two materials from which the first and second Abieiter be made to compensate. The reduced cross-sections introduced in the first Abieiter with the first, lower specific electrical conductivity allow it to melt through when an excessively high current flow occurs. In this way the current flow is interrupted. Due to the defined position outside the battery cell, attributed to the minimum distance above the sealing edge of the seal, a small end of the first Abieiters remains even after the occurrence of a melting outside the sealing of the battery cell, so that there is the possibility to discharge the battery cell. Furthermore, the heat acting on the battery cell, in particular formed as a pouch cell, is relatively low, so that neither the seal nor the battery cell is damaged.

Advantageously, the cross sections of the two Abieiter are also below

Considering the reduced cross section chosen so large that they can conduct a increased by a safety factor maximum allowable current. The triggering of the safety function, i. the melting is clearly visible from the outside.

Brief description of the drawings

With reference to the drawing, the invention will be described below in more detail. It shows:

1 shows a battery cell, in particular formed as a pouch cell, with a first Abieiter and a second Abieiter,

Figure 2 shows a first embodiment of a reduced cross section in

first Abieiter, FIG. 3 shows further embodiments for illustrating a reduced cross section in the first drain,

Figure 4 is a representation of a reduced cross section in the first Abieiter by

Slots and

Figure 5 shows a formation of a reduced cross section in the first Abieiter by a double-sided embossing.

Embodiments of the invention

The illustration according to FIG. 1 schematically shows a battery cell - here a pouch cell - with two tongue-shaped discharge elements.

The illustration according to FIG. 1 shows a battery cell 10 designed as a pouch cell 12. A number of battery cells 10 may be electrically interconnected, for example, in series or parallel, and in this case form battery modules or battery packs used as traction battery for vehicles, especially hybrid vehicles (HEV), plug-in hybrid vehicles (PHEV) or electric vehicles (EV) can be used.

From Figure 1 it is apparent that the battery cell 10 has a seal 14, at the top of which a sealing edge 16 is located. Over the sealing edge 16

protruding a first Abieiter 18 and a second Abieiter 20 are shown. The two Abieiter 18, 20 are formed in identical length with respect to each other. The first Abieiter 18 is carried out in a supernatant 22, on this over the sealing edge 16 projecting analogous to the supernatant 24, with which the second Abieiter 20 projects beyond the sealing edge 16 of the seal 14 of the battery cell 10.

The first conductor 18 formed in a width 26 is made of a material having a first specific electrical conductivity and made of, for example, aluminum or an aluminum alloy. The second conductor 20 is formed of a material having a second, higher specific electrical conductivity and made, for example, of copper or a copper alloy. In addition, it is possible to manufacture the first Abieiter 18 of an aluminum alloy and the second Abieiter 20 of a nickel alloy.

From the graphic representation of Figure 1 shows that the width 26 of the first Abieiters 18 is higher than the width 28 of the second Abieiters 20th A

A cross section of the first conductor 18 made of the material 30 having a first specific conductivity is identified by the reference numeral 58, while a cross section in which a second conductor 20 made of the material 32 having a higher specific electrical conductivity is 60 is designated. The lengths or protrusions 22, 24 in which the two Abieiter 18, and 20 protrude beyond the sealing edge, are identical.

In the first Abieiter 18 made of the material 30 with the first specific electrical conductivity, a reduced cross-section 62 is performed, wherein the execution of the reduced cross-section 62 can be made in several embodiments. The formed in the first Abieiter 18 reduced cross-section 62 can melt this at a high current flow occurring, so that an interruption of the current flow takes place. Following the solution proposed by the invention, the cross sections 58, 60, 62 of the first Abieiters 18 and the second Abieiters 20 adapted to each other that the ratio formed from the reduced cross section 62 of the first Abieiters 18 and the cross section 60 of the second Abieiters 20 the reciprocal Ratio of the electrical conductivities of the two materials 30 and 32, respectively. This is possible because the two Abieiter 18 and 20 each have an identical length, d. H. in the same supernatant 22, 24, based on the sealing edge 16 of the seal 14 of the battery cell 10 are formed. Accordingly, the following equation must be fulfilled:

Cross section _AUeUerl 62 ₌ conductivity _AUeUer2 MateriaB2

Conductor _Conductor2 60 Conductivity _Conductor Material30

Furthermore, the cross sections 58, 62 are to be selected such that they can lead to a maximum allowable current increased by a safety factor.

In Figures 2, 3, 4 and 5, several embodiments are shown as the reduced cross-section 62 in the first Abieiter 18, which contains the material 30 having the first lower specific conductivity may be formed. At the first Abieiter 18 is outside the battery cell 10 of the reduced

Cross section 62 formed. The reduced cross section is performed by at least 5%, typically by 20% to 30%, with respect to the original cross section 58 of the first extension 18. Therefore melts when too big

Current flow of the first Abieiter 18 at the reduced cross section 62 so that it serves as a battery cell fuse. The reduced cross section 62 is located

advantageously at a minimum distance 38, compare representations of Figures 2, 3, 4 and 5, above the sealing edge 16 of the seal 14 of the pouch cell 12 formed as a battery cell 10. This is during the melting process the

Heat transfer to the battery cell 10 and the sealing edge 16 low. These are therefore not damaged. It is also possible that the battery cell can be contacted again on the remaining projection of the first Abieiters 18 for a safe discharge.

FIG. 2 shows the configuration of the reduced cross-section 62 as a lateral taper 34. The width of the first protrusion 18, made of the material 30 with the first specific lower electrical conductivity, is denoted by reference numeral 26

characterized. As a material, for example, aluminum comes into question. The first absorber 18 has a lateral taper 34, which may be formed, for example, as two opposing notches 36. The lateral taper 34 is located at a minimum distance 38 with respect to the sealing edge 16 of the seal 14. The reduced cross-section 62, which is significantly smaller than the cross-section 58, results in the tongue-shaped first absorber 18 in its remaining regions outside the battery cell 10 having.

Figure 3 shows an alternative embodiment of the reduced cross section through

at least one hole. From the two illustrations according to FIG. 3, it can be seen that in the material 30 of the first armature 18, while maintaining a minimum distance 38, a bore 40 can be formed in a first diameter 42. Through this bore 40, the reduced cross section 62 in the first Abieiter 18 is shown. Instead of a bore 40 in the first diameter 42 and a plurality of juxtaposed bores 40, but then a second diameter 44, which is less than the first Diameter 42, be formed horizontally adjacent to each other in the material of the first Abieiters 18. The holes 40, which are formed in the second, smaller diameter 44, are on the one hand in a minimum distance 38 relative to the sealing edge 16 as shown in Figure 1 in the first Abieiter 18 and on the other hand form the desired reduced cross section 62 in the first Abieiter 18, the is formed from the material 30 having a first lower specific electrical conductivity.

The illustration according to FIG. 4 shows a further possible embodiment of a reduced cross section in the material of the first connector 18.

In the embodiment of Figure 4 18 slots 46 are formed in the material of the first Abieiters. The slit 46 may be either as a

Horizontal slit 48 be executed, which is located at a minimum distance 38 from the sealing edge 16 of the trained as a pouch cell 12 battery cell 10. Alternatively, as shown in FIG. 4, it is possible to form the slit 46 as at least one vertical slit 50, whereby the reduced cross-section 62 in the material of the first slender 18 according to the illustration in FIG. 1 is also obtained. According to the embodiment variants in FIGS. 2 and 3, the original width 26 of the first armature 18 remains outside the battery cell 10; only in the embodiment according to FIG. 2 does the width of the material of the first armature 18 decrease in the region of the lateral taper 34 one.

FIG. 5 shows a further embodiment of a reduced cross-section in the first conduit

As shown in FIG. 5, a double-sided embossing 54 is embodied in the material 30 having the first lower specific electrical conductivity. It is also possible to make an embossment 52 on the first Abieiter 18, which is executed only on one side of the first Abieiters 18. The width 26 of the first Abieiters remains unchanged. The formation of the reduced cross-section 62 is dependent on the depth at which the embossment marks 56 in the material 30 with the first lower specific electrical conductivity of the first Abieiters 18 is executed. The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, within the scope given by the claims a variety of modifications are possible, which are within the scope of expert action.

Claims

claims

A battery cell (10) with a seal (14), via which a first Abieiter (18) made of a material (30) having a first electrical conductivity and a second Abieiter (20) of a material (32) having a second electrical conductivity projecting, wherein the second electrical conductivity is higher than the first electrical conductivity, characterized in that a ratio of the cross sections (60, 62) of the Abieiter (18, 20) the reciprocal ratio of the electric

Conductivities of the materials (30, 32) of Abieiter (18, 20) corresponds.

2. Battery cell according to claim 1, characterized in that the two Abieiter (18, 20) an identical projection (22, 24) relative to a sealing edge (16) of the seal (14).

3. Battery cell according to one of the preceding claims, characterized in that that of the Abieiter (18, 20) with the material (30) having the first specific electrical conductivity outside the battery cell (10) has a reduced cross-section (62).

4. Battery cell according to one of the preceding claims, characterized in that the reduced cross-section (62) is reduced by at least 5%, preferably between 20% and 30% relative to the original cross-section (58) of the first Abieiters (18).

5. Battery cell according to claim 1, characterized in that the reduced cross-section (62) in the first Abieiter (18) in a

Minimum distance (38) relative to a sealing edge (16) of the

Seal (14) is located.

6. Battery cell according to one of the preceding claims, characterized in that the minimum distance (38) is a few millimeters, preferably between 2 mm to 3 mm.

7. Battery cell according to one of the preceding claims, characterized in that the reduced cross section (62) by at least one lateral taper (34) in the form of a notch (36) on one or both sides on the first Abieiter (18) is executed.

8. Battery cell according to one of the preceding claims, characterized in that the reduced cross-section (62) through at least one bore (40) in the first Abieiter (18), by one or more slits (46), in particular a horizontal slot (48) or at least a vertical slot (50) is given.

9. Battery cell according to one of the preceding claims, characterized in that the reduced cross section (62) by a one- or two-sided embossment (52, 54) on the first Abieiter (18) is formed.

10. Use of a battery cell (10), in particular a pouch cell (12) according to one of claims 1 to 9 in a traction battery of a hybrid vehicle (H EV), a plug-in hybrid vehicle (PH EV) or an electric vehicle (EV).