Battery cell and lead storage battery

Abstract

The utility model relates to a kind of battery units for lead storage battery, the battery unit has unit shell (2) and unit cover (3) sealing the unit shell (2) in liquid-tight mode, wherein positive electrode plate (5) and negative electrode plate (4) are alternately arranged in the unit shell (2) and electrolyte around electrode plate (4,5), wherein the positive electrode plate (5) and negative electrode plate (4) are electrically connected to at least one common pole (8,9,10,11) by means of corresponding unit connector (6,7), characterized in that positive pole (10,11) connected to positive electrode plate (5) via associated unit connector (7) is formed by lead alloy in the form of hard lead.

Description

Technical Field

[0001] This utility model relates to a battery cell for lead-acid batteries and a lead-acid battery. Background Technology

[0002] A typical lead-acid battery cell consists of a positive electrode plate, a negative electrode plate, and an electrolyte. The active material, i.e., the material that participates in the chemical reaction, is lead dioxide (PbO2) at the positive electrode and lead (Pb) at the negative electrode. The electrolyte is dilute sulfuric acid (H2SO4). A lead-acid battery is composed of multiple electrically connected battery cells as described above.

[0003] When a lead-acid battery discharges, lead, lead dioxide, and sulfuric acid react to produce lead sulfate (PbSO4) and water (H2O). During charging, the process reverses, with lead sulfate and water being converted back into lead, lead dioxide, and sulfuric acid. Unlike other types of batteries, the electrolyte participates in the reaction. In an undesirable side reaction, water (H2O) decomposes into oxygen (O2) and hydrogen (H2).

[0004] Lead-acid batteries typically consist of several positive and negative electrode plates. Electrode plates of the same polarity are connected to each other via tabs or unit connectors.

[0005] Separators are typically placed between the electrode plates to prevent contact between plates with different polarizations, thus preventing short circuits. However, at the same time, the separators must allow the migration of ions involved in the reaction. Therefore, they must be electrically insulating on the one hand, and ion-permeable on the other. They should also be acid-resistant and oxidation-resistant. Suitable materials for lead-acid batteries include, for example, polyethylene (PE), polyvinyl chloride (PVC), and phenolic resin.

[0006] Lead-acid battery components are typically housed in a plastic casing consisting of a housing and a cover. The terminals must extend from the cover. This is also known as a through-hole terminal design. The through-hole terminal design must prevent electrolyte leakage as much as possible.

[0007] Depending on the design of the positive and negative electrode plates, there are differences between different designs of lead-acid batteries.

[0008] Designed according to the GroE standard specified in DIN 40738 (German). Engeinbau, an acronym meaning large surface area plate, narrow mounting, refers to a positive electrode plate composed of pure lead plates with a layered surface structure. The positive electrode active material, PbO2, is then formed on the plates using a process known as chemical formation. The negative electrode plate is a cast grid made of lead or a lead alloy.

[0009] Other types include OPzS batteries (an acronym for the German Ortsfeste Panzerplatte Sonderseparation, meaning fixed protective plates, special isolation) and OCSM batteries (an acronym for the German Ortsfoste Kupfer(Cu)-Streeck Metall, meaning fixed copper (Cu) stretched metal), where the positive plate is a tubular plate and its core grid is cast from a lead-antimony alloy. Lead-clad fixed copper stretched metal grids (OCS M) are also used for industrial negative plate grids.

[0010] GroE and OPzS types, featuring standard drop-cast or die-cast grids, are typically designed as closed-cell batteries. In closed-cell batteries, the electrolyte flows freely in liquid form, meaning it is not stationary, and as mentioned earlier, the water splitting reaction produces oxygen or hydrogen at the electrodes. The generated gases must be vented from the battery casing primarily through vent plugs. Since decomposition also leads to water loss, water must be replenished periodically.

[0011] In contrast to sealed batteries, there are also hermetically sealed batteries, in which the electrolyte is fixed as a gel or encased in fibrous material. The oxygen produced does not escape but diffuses to the negative electrode, where it reacts to form water and lead sulfate. This prevents the formation of hydrogen gas. An example of a hermetically sealed design is the OPzV battery (an abbreviation of the German Ortsfeste PanzerplatteVerschlossen, meaning sealed, fixed protective plates).

[0012] GroE batteries offer advantages such as high corrosion resistance and long service life. For example, they are particularly suitable for short-term, high-current discharges, making them ideal for emergency power supply in power plants. Thus, GroE batteries can, for instance, ensure the operation of power plant control systems during failures and supply power to cooling systems via emergency power circuits.

[0013] Although lead-acid batteries—especially GroE batteries—have proven reliable in practice, there is still room for improvement.

[0014] For example, after a certain period of operation, lead-acid batteries are prone to short circuits. This may be due to conductive corrosive particles detaching from the battery terminals of the positive plate and coming into contact with the adjacent positive and negative electrode plates placed inside the battery casing, thus causing a short circuit.

[0015] The fundamental problem lies in the aging of the positive electrode plates made of lead. Even when used as intended, corrosion occurs, leading to the formation of lead dioxide. Unlike the lead matrix, lead dioxide is much larger, causing an expansion process over time due to corrosion, i.e., lead dioxide formation. This generates shear forces, causing the cell connectors made of hard lead to peel off or break. This means that lead particles may detach from the terminals or cell connectors and then fall into the battery casing under gravity.

[0016] This effect has a particularly detrimental impact on GroE batteries, which are designed for a lifespan of 20 years or more. In this respect, the negative characteristics of the corrosion effect have a significant impact on the long lifespan required for GroE batteries.

[0017] Due to the need to reduce internal resistance, pure lead is preferred in the prior art to achieve high conductivity and corrosion resistance. Preferably, in this case, both the positive electrode plate and the connectors that make electrical contact between the electrode plates are made of pure lead. Utility Model Content

[0018] Therefore, the problem to be solved by this utility model is to provide a battery cell for lead-acid batteries and a lead-acid battery having such a battery cell, so as to prevent known corrosion effects and / or the effects of corrosion effects on the primary battery system of the battery cell.

[0019] To address this problem, the present invention first proposes a battery cell for lead-acid batteries, the battery cell having a cell housing and a cell cover that seals the cell housing in a liquid-tight manner, wherein alternating positive and negative electrode plates and electrolyte surrounding the electrode plates are arranged within the cell housing, wherein the positive and negative electrode plates are electrically connected to at least one common terminal by means of corresponding cell connectors, wherein the positive terminal connected to the positive electrode plate via the associated cell connector is formed of a lead alloy in the form of hard lead.

[0020] The present invention advantageously provides an electrode post that is significantly more resistant to aging than the pure lead electrode posts used to date.

[0021] According to this invention, the positive electrode post is not made of pure lead, but of a lead alloy, in order to minimize peeling or breakage due to corrosion. Preferably, there is an insulator between pure lead and lead alloy at the transition between the connector and the post. The connector is still made of pure lead, but the post is no longer made of pure lead; instead, it is made of lead alloy.

[0022] It has been found that hard lead has sufficient conductivity, so any differences (if any) in the characteristic data of the battery cell in actual operation are negligible. This means that, for the first time, a battery cell, as well as a lead-acid battery, can be provided whose terminals remain corrosion-resistant even over relatively long periods. Therefore, the disadvantage known in the prior art, attributable to the fragmentation of the terminal material, which leads to a near inability to prevent short circuits between the positive and negative electrodes after a period of time, is avoided or at least mitigated.

[0023] In particular, for GroE batteries, the significantly reduced short-circuit tendency leads to a substantial increase in service life. While GroE batteries known in the prior art often fail to achieve their designed service life of 20 years or longer due to the aforementioned drawbacks, this is no longer the case for GroE batteries with battery cells according to this invention. Instead, batteries designed according to this invention can be used for an even longer period.

[0024] According to a preferred feature of this invention, a unit connector is also provided, which is significantly more resistant to aging than unit connectors used to date. Existing unit connectors are made of lead-antimony alloys, among other materials. It has now been found that using pure lead for the unit connector and hard lead for the electrode post produces an unexpected synergistic effect in improving overall corrosion. Therefore, according to a preferred feature of this invention, at least one unit connector connecting the positive electrode plate to the electrode post is made of pure lead. This ensures high conductivity in the connection path between the electrode plate and the electrode post. It has also been found that the negative corrosion effects of pure lead are almost entirely limited to the electrode post and do not affect the unit connector.

[0025] According to this invention, the positive electrode post is made of hard lead. Hard lead is a lead-antimony alloy with a relatively low antimony content. The hard lead is preferably composed of the following components:

[0026] -1wt.% to 13wt.% antimony;

[0027] - Residual lead

[0028] It has been found that hard lead achieves the required mechanical strength and corrosion resistance when composed of the following components:

[0029] -4wt.%~5wt.% antimony;

[0030] - Residual lead

[0031] In the context of this invention, the term "balance: lead" includes not only lead as the main alloying component, but also alloying components such as As, Se, Sn and Cu, as well as impurities, particularly those that cannot be technically or economically removed from the alloy and / or individual components due to the corresponding production methods of antimony and / or lead.

[0032] These trace amounts, which may be present individually or cumulatively in hard lead alloys in any way, include

[0033]

[0034] In this case, it is preferable that the total weight percentage of trace amounts of other metals does not exceed 0.4 wt.%.

[0035] According to a preferred feature of this invention, the unit connector that connects the positive electrode plate to the positive electrode post is adhesively connected to the positive electrode post. This connection is achieved through a metallic connection. Preferably, the material of one unit connector and the material of the other electrode post form an intermetallic phase in the boundary region. Preferably, this connection is formed by welding.

[0036] The known drawbacks in the prior art particularly affect the battery cells used in GroE batteries, and therefore the GroE batteries themselves, due to their long service life. Therefore, protection is specifically sought for a GroE battery cell. This GroE battery cell is characterized by the specific dimensions and area of ​​its electrode plates. This is because this type of battery must be able to provide consistently high performance over a long period to meet the technical requirements of its intended use. In this context, it is preferred that the height of both the positive and negative electrode plates is 200mm to 500mm, particularly 220mm to 420mm, preferably 229mm to 400mm, more preferably 229mm or 400mm. On the other hand, it is preferred that the width of both the positive and negative electrode plates is 120mm to 300mm, particularly 130mm to 270mm, preferably 139mm to 268mm, more preferably 136mm or 268mm. In particular, it is necessary to distinguish between two design types with different rated power. One type of GroE battery cell has electrode plates with a height of 229 mm and a width of 136 mm, while the other type has electrode plates with a height of 400 mm and a width of 268 mm. All the above dimensions should be understood to include possible tolerances within the range of ±0.5 mm to ±2 mm.

[0037] In addition to the selection of the electrode material according to this invention, or as an alternative, the effects of the aging process of the unit connector or electrode material can be reduced or prevented by setting up a retention device that mechanically intercepts and thus retains fragmented particles. In the simplest case, a mesh or grid is used, with the mesh size or grid spacing selected such that particles that may cause a short circuit are retained, while smaller particles not large enough to short-circuit two adjacent electrodes pass through and can therefore fall between the two plates to the bottom of the container.

[0038] Regarding the design of the mesh or grid used for retention, two embodiments are conceivable, and these embodiments can also be combined with each other. The first embodiment involves using a mesh sleeve fitted onto the corresponding pole. The second embodiment uses a plate-like mesh or grid that completely covers the cross-section of the housing above the electrode plate, below the corresponding unit connector. In this case, for the second embodiment, it is preferable to choose an inherently stable grid structure rather than a mesh device.

[0039] The reason for using preferred or alternative retention devices is that it has been shown that using optimized hard lead cannot completely prevent the pole from cracking or peeling off due to corrosion.

[0040] According to this invention, as an alternative or preferred option, at least one retention device is provided for intercepting particles that peel off from the positive electrode post, thereby preventing them from contacting the electrode plate and potentially causing a short circuit.

[0041] According to a preferred feature of this invention, the retention device is formed of a mesh and / or a grid. Preferably, the mesh and / or grid is made of an electrically insulating material. Furthermore, it is preferable that the mesh and / or grid is made of a sulfuric acid-resistant material.

[0042] Preferably, the mesh size of the mesh and / or grid is designed such that particles larger than a certain size that could cause a short circuit are trapped, while particles that would not cause a short circuit can pass through the trapping device unimpeded. Thus, particles are trapped according to the principle of size-based rejection. This measure is based on the understanding that particles detached from the electrode post or unit connector can only cause a short circuit if they are larger than a certain size. This is the case when a particle, due to its size, can at least span the distance between two adjacent positive and negative electrode plates. In contrast, smaller particles will not cause a short circuit at all.

[0043] According to the first preferred embodiment, the retention device is designed as a mesh sleeve surrounding the positive electrode post.

[0044] According to another preferred embodiment, the retention device is designed in the form of a planar mesh and / or grid, which is arranged (particularly unfolded) vertically between a positive electrode post (particularly the associated unit connector) on one side and an electrode plate on the other side. For this purpose, it is preferably attached to a fastening device provided by the unit housing. The fastening device may in particular be formed of a hook that interacts with, and in particular inserts into, a hook receiving portion formed on the mesh or grid.

[0045] In this case, it is preferable to specify that the mesh and / or grid extend such that its respective planar side substantially covers the entire cross-sectional area of ​​the cell housing. This ensures that particles detached from the terminals do not cross the retention device and fall into the plate space. This may occur, for example, if the location of the battery cell changes due to transportation or maintenance.

[0046] Due to its long service life, the known drawbacks in the prior art particularly affect the battery cells used in GroE batteries, thus affecting the GroE battery itself. This is why special protection of GroE battery cells is required. As mentioned earlier, GroE battery cells are characterized by the specific dimensions and surface area of ​​their electrode plates. Furthermore, they are characterized by a relatively long service life exceeding 20 years. Therefore, in GroE battery cells, forming the stabilizing device as an inherently stable grid has proven advantageous. This ensures that the stabilizing device functions throughout its entire service life.

[0047] In addition to the battery unit according to the present invention, the present invention also relates to a lead-acid battery formed by a plurality of battery units according to the present invention.

[0048] While a single battery cell may be sufficient in terms of performance and electrical characteristics for some applications, this is not the case in most cases. Instead, by combining multiple battery cells to form a larger lead-acid battery, its performance and characteristics can be easily expanded to meet specific application requirements. In this case, the combination is carried out via the corresponding terminals of the respective battery cells. For this purpose, cell connectors are preferably used, preferably in the form of cables with corresponding terminals.

[0049] Therefore, in order to reduce the tendency of short circuits, two synergistic measures were proposed to work together. On the one hand, the electrode material was changed from pure lead to a more corrosion-resistant hard lead alloy. On the other hand, a retention device was set up to separate and retain the broken electrode particles according to the principle of size exclusion. Attached Figure Description

[0050] The present invention will now be described in more detail using an embodiment.

[0051] Figure 1 A schematic perspective view of a battery cell according to the present invention is shown;

[0052] Figure 2 A schematic perspective view of the inside of a battery cell is shown. Detailed Implementation

[0053] Figure 1 A schematic perspective view of a large storage battery unit 1 according to the present invention is shown.

[0054] The battery unit 1 has a unit housing 2 and a unit cover 3, which seals the unit housing in a liquid-tight manner during final assembly.

[0055] Negative electrode plate 4 and positive electrode plate 5 are alternately arranged inside the unit housing 2, with partition plates 17 inserted between them. This allows for a more precise arrangement of the electrode plates. Figure 2 As shown in the diagram, when the battery unit 1 is in its final assembled state, the electrolyte, which is not shown in detail in the diagram, is also arranged inside the unit housing 2 and surrounds the electrode plates 4 and 5.

[0056] In the current configuration, electrode plates 4 and 5 have a height of 400 mm and a width of 268 mm. All dimensions given above should be understood as including tolerances within the range of ±0.5 mm to ±2 mm.

[0057] exist Figure 2 It can also be seen that the negative electrode plate 4 on one side and the positive electrode plate 5 on the other side are in electrical contact with each other. For this purpose, unit connectors are provided, namely unit connector 6 for the negative electrode plate 4 and unit connector 7 for the positive electrode plate 5.

[0058] With the aid of corresponding unit connectors 6 and 7, the negative electrode plate 4 on one side and the positive electrode plate 5 on the other side are electrically connected to the poles 8, 9, 10, and 11 passing through the opening in the unit cover 3. Therefore, a total of four poles are provided, with the negative electrode plate 4 and the positive electrode plate 5 each connected to two poles; that is, the negative electrode plate 4 is connected to poles 8 and 9, while the positive electrode plate is connected to poles 10 and 11. This factual relationship can also be seen from… Figure 2 As can be seen in the diagram.

[0059] Unit connectors 6 and 7 are electrically connected to the corresponding positive and negative electrode plates via current collectors 12 and 13 (also called electrode lugs), wherein current collector 12 is connected to the negative electrode plate 4 and current collector 13 is connected to the positive electrode plate 5.

[0060] The present invention also includes a configuration in which up to eight electrodes are provided, wherein the negative electrode plate 4 and the positive electrode plate 5 are connected to four positive electrodes on one side and four negative electrodes on the other side via associated unit connectors 6 and 7.

[0061] As the water content in the electrolyte decreases as expected during the operation of the battery cell 1, water needs to be added periodically. For this purpose, the cell cover 3 has a water inlet 14, which is sealed with an insert but is not liquid-tight and / or airtight, in order to avoid undesirable overpressure formation in the cell housing 2, especially during charging.

[0062] In the current configuration, terminals 8, 9, 10, and 11 all have inserts 15 made of copper and / or copper alloys. This advantageously reduces internal resistance compared to terminal designs without inserts.

[0063] The electrical connections between the electrode plates and the corresponding posts 8, 9, 10, and 11 are preferably made of a highly conductive material, or at least have regions with inserts made of a highly conductive material. This also minimizes internal resistance.

[0064] In the current configuration, the unit connectors are made of pure lead. On the other hand, the positive terminals 10 and 11 are made of hard lead, with a composition of 4.0 wt% to 4.5 wt% antimony and the balance being lead. The term "balance being lead" may also include trace amounts of other metals, but their total weight percentage shall not exceed 0.4 wt%.

[0065] Therefore, the unit connectors 6 and 7 provided according to this invention exhibit significantly improved aging resistance compared to previously used hard lead. As a result, peeling or breakage due to corrosion can be minimized. In such cases, separation of pure lead and lead alloy occurs at the transition between the unit connector 7 and the corresponding terminals 10 and 11 made of hard lead (Pb-Sb). Thus, the disadvantage known in the prior art, due to breakage of the terminal and unit connector materials, is avoided or at least delayed, as short circuits between the positive electrode plate 4 and the negative electrode plate 5 almost inevitably occur after a period of time. For the current GroE battery cell 1, this significant reduction in short-circuit tendency leads to a significant extension of service life.

[0066] In addition to the electrode material selected according to this invention, the battery unit 1 also has a retention device in the form of an inherently stable grid 16. Figure 2 In the diagram, only the grille 16 is shown at the front to clearly display the electrode plates 4 and 5. However, in reality, the grille 16 extends along the entire length of the unit housing 2. Furthermore, it can be seen that the grille 16 is positioned above the electrode plates 4 and 5, below the pole posts 10 and 11, and below the unit connectors 6 and 7. The grille 16 extends to both sides in the width direction below the respective unit connectors 6 and 7. Thus, the grille 16 is positioned in the height direction between one unit connector 6 and 7 and the other electrode plate 4 and 5.

[0067] The grid 16 according to this invention is used to mechanically intercept and thus retain particles detached from the poles 10, 11 – although the degree of such particle detachment is greatly reduced due to the material selection according to this invention, it may still not be negligible. In the present case, the mesh width of the grid 16 is chosen such that particles large enough to cause a short circuit are retained. Smaller particles not large enough to short-circuit the two adjacent electrode plates 4, 5 pass through the mesh of the grid 16 and can therefore fall between the two electrode plates 4, 5 to the bottom of the unit housing 2.

[0068] In addition, the grid 16 must be made of electrically insulating materials, especially plastic materials. The material of the grid 16 must also be resistant to electrolytes formed from dilute sulfuric acid.

[0069] The known disadvantages in the prior art particularly affect current GroE battery cells and GroE batteries formed therefrom, due to their long service life. In principle, a mesh can also be used as a retention device. However, since the retention device is currently designed as an inherently stable mesh 16, it is ensured that the retention device functions throughout its entire service life. Thus, the retention device of this invention is maintenance-free. A mesh-type retention device can also be used in GroE battery cells 1 if appropriate maintenance intervals are set.

[0070] A large number of according to Figure 1 The GroE battery cells 1 can be arranged in rows and electrically connected to each other to form a GroE battery. The battery cells 1 arranged in this way are housed within a higher-level battery casing. The battery cells 1 are arranged in rows with gaps between them. This allows cooling airflow between the battery cells 1, thereby achieving the desired cooling effect on the battery cells 1 during operation.

[0071] Figure Labels

[0072] 1GroE battery unit

[0073] 2-unit housing

[0074] 3-unit cover

[0075] 4 negative electrode plates

[0076] 5 positive electrode plates

[0077] 6-unit connector

[0078] 7-unit connector

[0079] 8 poles

[0080] 9 poles

[0081] 10 poles

[0082] 11 poles

[0083] 12 current collectors

[0084] 13 current collectors

[0085] 14 water inlets

[0086] 15 inserts

[0087] 16-plate grid

[0088] 17 partitions

Claims

1. A battery cell for a lead-acid battery, the battery cell having a cell housing and a cell cover that liquid-tightly seals the cell housing, wherein positive electrode plates and negative electrode plates, and an electrolyte surrounding the electrode plates, are alternately arranged within the cell housing, wherein both the positive and negative electrode plates are electrically connected to at least one common terminal by means of corresponding cell connectors, characterized in that, The positive electrode post, connected to the positive electrode plate via an associated unit connector, is formed of a lead alloy in the form of hard lead.

2. The battery unit according to claim 1, characterized in that, At least one unit connector that connects the positive electrode plate to the pole is made of pure lead.

3. The battery unit according to claim 2, characterized in that, The unit connector and the positive terminal are integrally connected to each other, wherein the integral connection is formed through an intermetallic phase.

4. The battery unit according to claim 1, characterized in that, The height of both the positive electrode plate and the negative electrode plate is 200 mm to 500 mm.

5. The battery unit according to claim 1, characterized in that, The width of both the positive electrode plate and the negative electrode plate is 120 mm to 300 mm.

6. The battery unit according to claim 1, characterized in that, At least one retention device is provided to intercept particles that detach from the positive electrode post, thereby preventing them from contacting the electrode plate.

7. The battery unit according to claim 6, characterized in that, The retention device is formed of a mesh and / or a grid.

8. The battery unit according to claim 7, characterized in that, The mesh width of the net and / or grid is configured such that particles larger than a certain size that may cause a short circuit are trapped, while particles that will not cause a short circuit can pass through the trapping device unimpeded.

9. The battery unit according to claim 6, characterized in that, The retention device is designed in the form of a mesh sleeve surrounding the positive electrode post.

10. The battery unit according to claim 6, characterized in that, The retention device is designed in the form of a planar mesh and / or grid, which is arranged vertically—particularly unfolded—between a positive pole on one side, particularly an associated unit connector, and an electrode plate on the other side.

11. The battery unit according to claim 10, characterized in that, The mesh and / or grid extend such that their respective planar sides substantially cover the entire cross-sectional area of ​​the unit housing.

12. The battery unit according to claim 6, characterized in that, The retention device is designed as an inherently stable grid.

13. A lead-acid battery, characterized in that, It is formed from a plurality of battery cells according to any one of claims 1 to 12.

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