Battery and method for producing a battery

Abstract

Proposed is a battery, in particular for motor vehicles, comprising a battery box (2) which has at least one cell (1) and is closed by a cover (5), wherein: in the at least one cell (1), there are arranged an electrode plate (3), an electrolyte liquid (4) which surrounds the electrode plate (3), and a device for mixing the electrolyte liquid (4) in the at least one cell (1); the device comprises an insert part (7) arranged in the at least one cell (1); and the insert part (7) forms at least one flow path (10) which fluidically connects an upper region to a lower region of the at least one cell (1). The battery is characterized in that the insert part (7) is fixed to the battery box (2) and / or to the cover (5) at a connection (8) between the battery box (2) and the cover (5). Also proposed is a method for producing such a battery.

Description

[0001] ACCUMULATOR AND METHOD FOR MAKING AN ACCUMULATOR

[0002] The invention relates to an accumulator, in particular for motor vehicles, comprising an accumulator box having at least one cell and closed with a lid, wherein in the at least one cell an electrode plate, an electrolyte liquid surrounding the electrode plate and a device for mixing the electrolyte liquid in the at least one cell are arranged, wherein the device has an insert arranged in the at least one cell and wherein the insert forms at least one flow path that connects an upper region with a lower region of the at least one cell.

[0003] Furthermore, the invention relates to a method for manufacturing such an accumulator.

[0004] In batteries with liquid electrolyte, gradients in acid density develop during operation. Acid is consumed when the battery is discharged. For example, in a lead-acid battery, lead sulfate and water are produced from the lead in the electrodes and the sulfuric acid in the electrolyte when electrical energy is released. This causes the acid density to decrease in the immediate vicinity of the electrodes. During charging, this process is reversed; that is, acid is "generated" using electrical energy. This causes the acid density to increase in the immediate vicinity of the electrodes. In both cases, diffusion processes equalize the different acid densities to a certain extent. However, gradients remain.

[0005] A further problem arises from the fact that, in addition to the gradient across the electrodes, a gradient also forms along the electrodes. Sulfuric acid, which is heavier than water, sinks downwards towards the bottom of the battery under the influence of gravity. This increases the concentration in the lower part of the accumulator or battery, leading to a phenomenon known as acid stratification. Severe acid stratification can result in irreversible damage to the electrodes.

[0006] Acid stratification leads to two main disadvantages. First, it reduces the battery's capacity, potentially losing up to 20%. This is particularly problematic when sufficient storage capacity is needed but space is limited. Second, reversible acid stratification can cause irreversible damage to the electrodes. The lower acid density in the upper region, due to the reduced resistance in this area, leads to overcharging during operation. Conversely, the higher acid density in the lower region, if acid stratification persists, causes corrosion and premature electrode wear. Therefore, it is highly desirable to prevent acid stratification as effectively as possible.

[0007] Various devices and methods for counteracting acid stratification are already known in practice. For example, EP 3 467 898 B1 discloses an accumulator of the type mentioned above, in which a separate insert 7 in the form of a wall element 7 is arranged in a cell 3 of an accumulator 1. The insert 7 projects above the usual electrolyte level, so that when the electrolyte fluid moves, some of it can spill over the top edge of the insert 7. Due to a hydrostatic effect, the spilled electrolyte fluid can flow along a flow path formed by the insert 7 from an upper region of the cell 3 to a lower region of the cell 3, thereby mixing the electrolyte fluid and counteracting acid stratification.

[0008] Furthermore, parts from EP 2 660 894 B1, EP 2 474 059 B1 and the

[0009] DE 10 2020 106 143 A1 discloses corresponding devices for mixing the electrolyte fluid in a cell of an accumulator. The known devices are formed, for example, by a partition or specially shaped inserts. According to Fig. 28 of EP 2 474 059 B1, such an insert 820 is fixed to a cover 807 of an accumulator 800.

[0010] With known accumulators and accumulator manufacturing processes, one problem is that the inserted insert is not securely fixed within the accumulator and can therefore, in the worst case, move into a position where proper mixing of the electrolyte fluid is no longer guaranteed. Reference can be made here to the separate insert known from EP 3 467 898 B1. On the other hand, while it is known from EP 2 474 059 B1 to fix such an insert, this involves a fixing process on the accumulator lid. Therefore, to complete the accumulator manufacturing process, the lid with the attached insert must be precisely inserted into the accumulator housing, which already contains the electrode plates, in a further process step. This precise insertion requires great care and is therefore time-consuming.

[0011] The present invention is therefore based on the objective of designing and further developing an accumulator and a method of the type mentioned at the outset in such a way that unwanted acid stratification is reliably prevented using structurally simple means. A corresponding method should be particularly well suited for the production of an accumulator designed according to the invention.

[0012] The aforementioned problem is solved according to the invention, on the one hand, by an accumulator with the features of claim 1. According to this claim, the accumulator discussed at the outset is characterized in that the insert is fixed to the accumulator box and / or the lid at a connection between the accumulator box and the lid.

[0013] Furthermore, the aforementioned problem is solved according to the invention by a method for manufacturing an accumulator with the features of claim 10. According to this method, the method is designed and further developed such that the insert is fixed to the accumulator housing and / or the lid at a connection between the accumulator housing and the lid. In accordance with the invention, it has first been recognized that the aforementioned problem is solved in a surprisingly simple manner by a clever design of the accumulator. For this purpose, the insert is further and specifically fixed according to the invention such that it is fixed to the accumulator housing and / or the lid at a connection between the accumulator housing and the lid. It is taken into account that the accumulator housing and the lid must be securely connected to each other for the manufacture of the accumulator.And this is precisely where the present invention comes in, namely by fixing the insert to this connection, which is necessary anyway in the manufacture of the accumulator. Thus, on the one hand, a secure fixing of the insert is provided, and on the other hand, the manufacturing effort for the accumulator is reduced, whereby the insert is not fixed at any other arbitrary point on the accumulator housing or lid – as in the prior art described above – but at a point that must be taken into account in the manufacture of the accumulator anyway, namely at the connection between the accumulator housing and the lid.

[0014] Consequently, the accumulator and the accumulator method according to the invention provide an accumulator and a method by which unwanted acid stratification is reliably prevented using structurally simple means, thereby enabling a simplified accumulator manufacturing process compared to the prior art. Accordingly, this accumulator method according to the invention is particularly well suited for manufacturing the accumulator designed according to the invention.

[0015] In a particularly simple and straightforward manner, the insert can be integrated into the connection between the battery box and the lid. This ensures a particularly secure and easy fixation of the insert together with the battery box and the lid. More specifically, the connection can be achieved by welding or bonding between the battery box and the lid. Such connections are easy to implement and guarantee exceptional stability.

[0016] The insert can be welded, melted, or glued together with the battery box and the lid. This connection between the three components—the battery box, the lid, and the insert—can therefore be carried out essentially simultaneously in one operation, or at least in quick succession. First, two of the three components are joined, and shortly thereafter, while the joint is still cold and / or hardened, the third component is added. In any case, this avoids the need for multiple separate joining operations, such as first attaching the insert to the lid and then attaching the lid with the insert to the battery box.

[0017] Furthermore, to ensure secure fixation of the insert, it can rest against an inner wall of the battery box or at least one cell. This provides additional positional stabilization of the insert during installation and / or in its installed state.

[0018] Also with a view to securely fixing the insert, the inner wall in the lower area of ​​at least one cell may have a recess. Such a recess in the inner wall can serve to further stabilize the insert's position during installation and / or in the installed state.

[0019] To easily provide a particularly effective and safe flow path between the upper and lower regions of the cell, the insert can have at least one passage at its lower end, and thus in the lower region of the at least one cell. This allows any electrolyte fluid that overflows in the upper region of the insert to be safely discharged into the lower region of the cell via the lower region of the insert.

[0020] To reliably collect any electrolyte fluid that may overflow in the upper part of the cell, the insert can have a preferably funnel-shaped collection area at its upper end. The insert can also be easily fixed to the connection between the battery housing and the lid using this collection area.

[0021] In a further embodiment of the accumulator, the insert can have at least one partition extending longitudinally to form one or more flow paths. Such a partition contributes to the mechanical stabilization of the insert against undesired torsions.

[0022] The insert can be made of acid-resistant plastic. For example, when a vehicle with a battery is in motion, the electrolyte fluid inside the battery—such as diluted sulfuric acid in a lead-acid battery—is moved. This movement causes the electrolyte solution to slosh over the insert and be forced downwards by hydrostatic pressure. Thus, the electrolyte solution is automatically circulated as the vehicle moves.

[0023] There are now various ways to advantageously develop and further refine the teaching of the present invention. For this purpose, reference is made, on the one hand, to the claims subordinate to claim 1 and, on the other hand, to the following explanation of a preferred embodiment of the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiment of the invention with reference to the drawing, generally preferred embodiments and further developments of the teaching are also explained. In the drawing, Fig. 1 shows, in a schematic and cutaway side view, an embodiment of an accumulator according to the invention in an operating state in which electrolyte fluid spills into a receiving area of ​​an insert.

[0024] Fig. 2 shows a schematic and cutaway side view of the embodiment according to Fig. 1 in a further operating state in which no further electrolyte fluid spills into the receiving area of ​​the insert.

[0025] Fig. 3 shows a schematic and cutaway side view of the embodiment according to Fig. 1 in a further operating state, in which the electrolyte level in the receiving area is the same as in the rest of the accumulator.

[0026] Fig. 4 shows the insert of the embodiment from Fig. 1 in a top view, a side view and a bottom view.

[0027] Fig. 5 shows two further side views of the insert part of the embodiment from Fig. 1, and

[0028] Fig. 6 shows two perspective views of the insert part of the embodiment from Fig. 1.

[0029] Figures 1 to 3 show, in schematic and cutaway side views, the basic structure of an embodiment of the accumulator according to the invention, which illustrates the operating principle of hydrostatic electrolyte circulation. The accumulator is shown in three operating states.

[0030] Figures 1 to 3 show, more precisely, a battery comprising a battery box 2 divided into cells 1, with electrode plates 3 arranged in the cells 1. In the operating state of the battery, the electrode plates 3 are surrounded by an electrolyte liquid 4, more precisely by an acid.

[0031] Figures 1 to 3 further show that the accumulator box 2 is closed with a lid 5. A device for mixing the electrolyte 4 is provided on an inner wall 6, this device comprising an insert 7 which is fixed to a connection 8 between the accumulator box 2 and the lid 5. In this embodiment, the connection 8 is a weld. The insert 7 has a receiving area 9 at its upper end for any overflowing electrolyte 4, which, after overflowing, is guided from an upper region of the cell 1 to a lower region of the cell 1 along a flow path 10 formed by the insert 7 together with the inner wall 6, due to the presence of hydrostatic pressure. To allow outflow from the flow path 10 into the lower area of ​​the cell 1, the insert 7 has passages 11 at a lower end of the insert 7.

[0032] The insert 7 is positioned on the inner wall 6 when fixed at the connection 8. The insert 7 extends downwards to a recess 12 of the accumulator housing 2, and more precisely to the inner wall 6.

[0033] Fig. 1 shows a state of electrolyte fluid 4 overflowing from an upper area of ​​the cell 1 into the receiving area 9 of the insert 7, as can occur, for example, when an accumulator installed in a motor vehicle moves during driving of the motor vehicle.

[0034] Fig. 2 shows a state after this overflow, in which the electrolyte fluid 4 in the receiving area 9 has a higher level than the resting level already reached in the rest of the accumulator. In this state, due to hydrostatic pressure, the electrolyte fluid 4 flows from the receiving area 9 along the flow path 10 and through the passages 11 into the lower region of the cell 1 in order to achieve the desired mixing of the electrolyte fluid 4 in the accumulator.

[0035] Fig. 3 shows a state following the state shown in Fig. 2, in which the levels of the electrolyte fluid 4 in the receiving area 9 and in the remaining part of the accumulator are at the same resting level.

[0036] Fig. 4 shows the insert 7 of the embodiment from Fig. 1 in a top view, a side view, and a bottom view. In the top view, the receiving area 9 and the three passages 11 are visible. The receiving area 9 has a substantially rectangular cross-section. In the side view, two partitions 13 are visible, so that the insert 7 ultimately has three flow paths 10. In the bottom view, the passages 11 and the two partitions 13 of the insert 7 are also visible.

[0037] Fig. 5 shows the insert 7 of the embodiment from Fig. 1 in two further side views. The partitions 13 are not visible in these side views.

[0038] Fig. 6 shows the insert 7 of the embodiment from Fig. 1 in two perspective views. The receiving area 9 and the passages 11 are clearly visible in both views. Furthermore, the perspective view shown on the right side of Fig. 6 clearly shows how the two partitions 13 ultimately form three flow paths 10. The insert 7 has an uppermost edge 14 of the receiving area 9. This uppermost edge 14 serves to fix the insert 7 to the connection 8.

[0039] Regarding features that cannot be discerned from the figures, reference is made to the general part of the description to avoid repetition.

[0040] Finally, it should be expressly pointed out that the embodiment of the accumulator according to the invention described above serves only to discuss the claimed teaching, but does not limit it to the embodiment described above.

[0041] Reference symbol list

[0042] 1 cell

[0043] 2 accumulator boxes

[0044] 3 Electrode plate

[0045] 4 Electrolyte liquid

[0046] 5 lids

[0047] 6 Inner wall

[0048] 7 insert

[0049] 8 connection

[0050] 9 Recording area

[0051] 10 Flow path

[0052] Round 11

[0053] 12 Return

[0054] 13 Partition wall

[0055] 14 top edge

Claims

Claims 1. Accumulator, in particular for motor vehicles, comprising an accumulator box (2) having at least one cell (1) and closed with a lid (5), wherein in the at least one cell (1) an electrode plate (3), an electrolyte liquid (4) surrounding the electrode plate (3) and a device for mixing the electrolyte liquid (4) in the at least one cell (1) are arranged, wherein the device has an insert (7) arranged in the at least one cell (1) and wherein the insert (7) forms at least one flow path (10) which connects an upper region with a lower region of the at least one cell (1) by flow, characterized in that the insert (7) is fixed at a connection (8) between the accumulator box (2) and the lid (5) on the accumulator box (2) and / or the lid (5).

2. Accumulator according to claim 1, characterized in that the insert (7) is integrated into the connection between the accumulator box (2) and the lid (5).

3. Accumulator according to claim 1 or 2, characterized in that the connection (8) is a weld or bond between the accumulator box (2) and the cover (5).

4. Accumulator according to claim 3, characterized in that the insert part (7) is welded or glued together with the welding or bonding between the accumulator box (2) and the cover (5).

5. Accumulator according to one of claims 1 to 4, characterized in that the insert (7) rests against an inner wall (6) of the accumulator box (2) or of the at least one cell (1).

6. Accumulator according to claim 5, characterized in that the inner wall (6) has a recess (12) in the lower area of ​​the at least one cell (1).

7. Accumulator according to one of claims 1 to 6, characterized in that the insert (7) has at least one passage (11) at a lower end of the insert (7) and thus in the lower region of the at least one cell (1).

8. Accumulator according to one of claims 1 to 7, characterized in that the insert (7) has at an upper end of the insert (7) a preferably funnel-shaped receiving area (9) for overflowing electrolyte liquid (4).

9. Accumulator according to one of claims 1 to 8, characterized in that the insert (7) has at least one partition (13) extending in the longitudinal direction of the insert (7) to form one or more flow paths (10).

10. Method for manufacturing an accumulator, in particular an accumulator according to any one of claims 1 to 9, wherein the accumulator comprises an accumulator box (2) having at least one cell (1) and closed with a lid (5), wherein in the at least one cell (1) an electrode plate (3), an electrolyte liquid (4) surrounding the electrode plate (3), and a device for mixing the electrolyte liquid (4) in the at least one cell (1) are arranged, wherein the device comprises an insert (7) arranged in the at least one cell (1), and wherein the insert (7) forms at least one flow path (10) which connects an upper region with a lower region of the at least one cell (1), characterized in that the insert (7) is fixed at a connection (8) between the accumulator box (2) and the lid (5) on the accumulator box (2) and / or the lid (5).

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