DE102014115330A1 - Battery pack and method for mounting a battery pack - Google Patents

Abstract

To provide a battery pack that is easy to manufacture, sufficient heat dissipation during assembly and during operation of the battery pack (10) provides a reliable electrical connection between the terminal structures (14) and the terminals (33, 34) of the battery cells (11) , as well as the failure of a single battery cell (11), a battery pack (10) is provided, comprising: at least two battery cells (11), each battery cell (11) having a positive and a negative electrical connection contact (33, 34), wherein at least one of the electrically positive connection contacts (33) or the electrically negative connection contacts (34) of the battery cells (11) is assigned a connection structure (14), each battery cell (11) being connected to the connection structure (14) via at least one connection element (15, 51) ), wherein a cross-section of the respective connection element (15, 51) to a predetermined maximum current a battery cell (11) is adapted, wherein the connection element (15, 51) on a battery cells (11) facing side of the connection structure (14) is attached. Each connection structure (14) has a current resistance which corresponds to the sum of the individual currents of each connected battery cell (11).

Description

The present invention relates to a device for receiving battery cells, also referred to below as a battery pack, and to a method for assembling or producing a battery pack.

Battery packs are used in many different electrically powered devices, especially in electric vehicles, in electrically powered bicycles, in battery powered tools, portable computers, and telephones, etc. These rechargeable batteries are mostly used in these battery packs. Nowadays, rechargeable lithium-based battery cells are used in such battery packs. Rechargeable batteries are characterized by the fact that they can be recharged after a first discharge process again. However, this requires a corresponding circuit for monitoring the charging and discharging process, which is adopted for example by a battery management system. When connecting the individual cells within a battery pack, a reliable electrical connection between the connection structures of the battery pack and the electrical contacts of the battery cell is essential. This contact must be both during operation, i. work reliably under appropriate mechanical as well as thermal and electrical loads as well as over the entire life of the electrical device.

Furthermore, especially in the case of large battery packs with several hundred battery cells during charging and also during discharging, very large currents occur at the connection areas of the battery pack. Where large currents are flowing, a great deal of heat is generated, the transfer of which to the battery cells must be avoided, since battery cells, in particular lithium-ion cells, can outgas with uncontrolled heat supply or even explode. Therefore, a variety of technologies are used in the prior art to avoid heat exposure to the cells during assembly of the battery pack and during the charging and discharging process. For example, additional cooling is used to avoid heat build-up during the charging and discharging process. However, it is also known to arrange the individual battery cells of a battery pack so that they are adequately ventilated so that the generation of heat within the battery pack above a permissible value is avoided as far as possible. However, the effect of heat during the assembly process must be taken into account, in particular during the connection process.

The attachment of terminal structures of the battery pack to the individual electrical terminals of the cells is often done by spot welding or soldering. This leads locally to very high heat effects on the individual cells, but is required to produce a reliable electrical connection. Another aspect in the construction of battery packs is that of the sometimes several hundred battery cells within a battery pack during the service life of the battery pack individual battery cells may fail due to inhomogeneities within the cells, the failure is often caused by a reduced internal resistance and consequently to a increased current flow leads to the connection structures of the battery pack. This increased current flow can lead to uncontrolled heat development in the cell and also in the neighboring cells, which can lead to a chain reaction, so that the whole battery pack uncontrollably outgass or explode. In order to avoid such influences, a battery pack is required, which is easy to manufacture and avoids by its construction one or more of the above-mentioned problems.

The object of the invention is therefore to provide a battery pack, which is easy to manufacture, provides sufficient heat dissipation during assembly and during operation of the battery pack, a reliable electrical connection between the terminal structures and the terminals of the battery cells, as well as the failure of a single battery cell coped.

The object is solved by the features of the independent claims.

The invention is based on the idea of providing in a battery pack a connection structure and corresponding electrical connections to the connection contacts of the battery cells, which on the one hand allow a uniform distribution of the charging current during charging and reliably transport the high current flow of the many individual battery cells to connection areas during discharging, without the charge to excessively burden individual battery cells with heat. In addition, it is ensured by the inventive connection between the electrical connection contacts of the battery cells and the connection structure that in case of failure or failure of a single battery cell and an extremely high current due to the fault reliable decoupling of the individual battery cells is ensured.

According to a solution of the above object, a battery pack comprises: at least two battery cells, each battery cell having a positive and a negative electrical connection contact has at least the electrically positive terminal contacts or the electrically negative terminal contacts of the battery cells is assigned a connection structure, each battery cell is connected via at least one connection element to the connection structure, a cross section of the respective connection element is adapted to a predetermined maximum current of a battery cell, and the connection element at a The battery cell facing side of the connection structure is attached. Each connection structure has a current resistance equal to the sum of the individual currents of each connected battery cell.

Preferably, a first connection structure can be assigned to the electrically positive connection contacts of the battery cells and a second connection structure can be assigned to the electrically negative connection contacts of the battery cells, wherein the connection elements are respectively attached to the sides of the connection structures which face the battery cells.

Preferably, the battery pack may further include at least one support structure for receiving the at least two battery cells.

Preferably, the support structure may have a surface which is directed to the connection structure, wherein the surface of connection openings is broken.

In the assembled state, the connection structure can preferably rest on the surface of the holding structure and the connection elements can penetrate the connection opening.

Preferably, a first holding structure can be arranged on the side of the positive electrical connection contacts and a second holding structure can be arranged on the side of the negative electrical connection contacts.

Preferably, at least one fastening element can be arranged at predetermined locations between the first and second retaining structure in order to hold the two retaining structures together with the inserted battery cells. There may also be several fasteners.

Alternatively or additionally, at least one or more further fastening elements may be provided in order to hold the two connection structures together with the holding structures receiving the battery cells.

Preferably, the fastener may be formed of electrically non-conductive material or surrounded by an electrically insulating material.

According to another solution of the above object, there is provided a method of manufacturing a battery pack, comprising the steps of: inserting at least two battery cells into a support structure, connecting a terminal structure with one connection element per battery cell on a first side of the connection structure, placing the connection structure with the fastened connection elements on the support structure, wherein the connection elements are attached to the first side of the connection structure, which faces the battery cells, connecting the connection elements, which are connected to the connection structure, with electrical connection contacts of the battery cell.

By attaching the connection elements on the side of the connection structure, which is directed in the mounted state to the battery cells, i. the connection structure is reversed after attaching the connection elements, the connection points are facing the holding structures or battery cells. This has two decisive advantages. Thus, the joints are protected on the one hand against external, especially mechanical influences and damage can be avoided. On the other hand, the connection elements have to be bent less strongly, since the distance to the connection contacts becomes smaller by the material thickness of the connection structures. This also has positive influences on the welded joints, both on the connection structures and on the connection contacts, since less material stresses act on the connection elements. In addition, the handling when connecting / welding is improved by the less curved connection elements.

According to a solution of the above object, a battery pack comprises at least two battery cells. Each battery cell has an electrically positive and an electrical negative terminal contact. The electrically positive connection contacts of the battery cells are each assigned a first connection structure, and the electrically negative connection contacts of the battery cells are assigned a second connection structure.

Since the battery cells within the battery pack receive a current when charging, which is controlled by the battery management system or the charger, and deliver a high current during discharging, which is determined by the load request, each connection structure has a current strength which is the sum of the individual currents of the connected Battery cells of the battery pack corresponds.

The electrical connection between the first connection structure and the respective electrically positive connection contacts of the battery cells contained in the battery pack and between the second connection structure and the respective electrically negative connection contacts of the battery cells contained in the battery pack is provided in each case by a connection element. In this case, each of the connection contacts of each battery cell is correspondingly connected to at least one connection element, wherein each connection element is connected to the associated connection structure. That is to say the current resistance of the connection structure is substantially greater than the current resistance of the respective connection element.

According to the invention, the cross section of the connection element, which establishes the electrical connection between the electrical connection of the battery cell and the connection structure, is adapted to a predetermined maximum current of a single battery cell. This ensures that when discharging only a maximum predefined or permissible current can flow through the battery cell, as at a higher current, which can occur especially in case of failure by a low internal resistance of the battery cell, the connection element melts and thus decoupling of the affected battery cell causes the battery pack. On the other hand, the connection elements with the defined cross-section during the charging process act as a current limiting element, so that only a limited current can flow into the battery cell. This achieves an equal distribution of the current or a compensation of the current flowing to the battery cells. It prevents battery cells that are closer to the power supply from charging faster or receiving higher power than battery cells that are further away from this connection area.

Preferably, the battery cells located in the battery pack are connected in a parallel connection. That is, the respective positive or negative terminal contacts of the battery cells are each assigned to a connection structure. This ensures that the electrically positive terminal contacts and the electrically negative terminal contacts are each on one side, for example, the top or bottom of the battery pack and the charging or discharging through a first connection structure for the electrically positive terminal contacts and a second connection structure can be added or removed for the electrically negative terminal contacts.

In a further embodiment, at least one holding structure for receiving the at least two battery cells is provided. By means of this holding structure, a physical fixation of the battery cells is achieved. The battery cells are mechanically fixed by way of the holding structure, so that the smallest possible mechanical holding forces act on the connection elements or connection structures and they are not under mechanical stress.

In a particular embodiment, the battery cells are designed as round cells, which have an electrically positive terminal contact on a first end face and have an electrically negative terminal contact on the opposite end face. However, the invention is not limited to such round cells. It can also Pouchzellen, as well as flat cells are used, which consist of several round cells, wherein the electrical connection contacts of the battery cells used in each case can also be arranged on the same side of the battery pack. However, then results in a different arrangement of the connection structures. Optionally, a plurality of electrically separate connection structures on one side of the battery pack are required.

In a further particular embodiment, a first and a second holding structure are provided, which are each arranged on opposite end faces of the battery cells, so that in each case the opposite end faces of the battery cells are received with the corresponding electrically positive and electrically negative terminal contacts in the two support structures. For this purpose, the holding structure preferably has receiving openings which are provided for receiving at least part of the outer shape of each battery cell of the battery pack. Through this receiving opening, the battery cell can be added during the assembly process in the support structure and is there sufficiently well fixed so that they can not change their position. During the attachment of the connection elements and the connection structures, the position of the electrically positive and electrically negative connection contacts can thus no longer be changed. By means of the configuration of the holding structure, it is also possible to define a distance between the individual battery cells, in which a distance between the receiving openings is selected or designed so that a sufficient ventilation between the individual battery cells of the battery pack is possible. For this purpose, the receiving openings of the first and second holding structures each have a predetermined depth, so that the respective battery cells can be used there safely enough. In this case, the receiving opening is designed so that the battery cells can not fall out. Thus, a clamping connection is provided by the receiving opening.

Furthermore, each of the support structures has a plurality of connection openings, wherein over or through the connection openings are contacted by the electrical connection contacts of the battery cells. Each connection opening of the holding structure is associated with a receiving opening. That is, the connection element is guided through the connection opening to the receiving opening and thus brought to the electrical connection contact of the battery cells. For this purpose, the respective connection opening communicates with the corresponding receiving opening. Between the connection opening and the receiving opening thus exists a through hole. In order to prevent falling out or slipping out of the battery cells from the receiving opening in the direction of the connection opening, the connection opening is smaller than the receiving opening.

In addition, a mechanical protection of the connection side or the electrical connection of the battery cell is provided by the smaller connection opening, which is directed to the outside, since at least one projection or a peripheral edge of the receiving opening, a part of the front side of the battery cells is covered and Thus, mechanical damage to the electrical connection or the isolation of the cell can be prevented. On the strength of the edge or projection in the receiving opening, a distance between the receiving opening and connection opening can be adjusted. The greater this distance, the higher the mechanical and thermal protection of the electrical connection contact of the individual battery cell.

As already explained above, each holding structure has receiving openings and connection openings. The terminal openings are arranged on a connection side of the support structure, wherein the receiving openings are arranged on a receiving side of the support structure. The receiving side with the receiving openings serves to receive the battery cells, wherein the connection side is provided for the electrical access from the outside to the electrical connection contact of the battery cells. That is, the terminal sides of the respective support structures are directed outward at the battery pack. The receiving sides of the support structures are directed inwardly with respect to the battery pack. That is, when considering a single support structure, the receiving side and the connection side are opposite each other and thus form a top and bottom of the support structure. In this case, the receiving openings are arranged on the receiving side of the support structure in order to provide structural support for the battery cells.

The terminal sides of the support structures are each covered with the connection structures. Thus, the first and second terminal structures are respectively disposed on a terminal side of the first and second support structures, wherein the battery cells are disposed between the first and second support structures.

For supplying the charging current or for discharging the discharge current, each of the connection structures has a battery pack connection region. In this case, the battery pack connection region is arranged on an outer edge or an outer edge of the connection structure and preferably protrudes therefrom or beyond the outer dimension of the battery pack. The battery pack connection areas serve either for connection to a charger or to a consumer. When interconnecting multiple battery packs together, they serve to connect battery terminal areas of multiple battery packs.

In order to ensure a uniform flow of current through the corresponding connection structures, the battery pack connection regions are arranged diagonally over the battery pack. That is, a battery pack terminal portion on the electrically positive side is disposed, for example, on the left upper side, whereas the battery pack terminal portion of the electrically negative side is disposed on the bottom of the battery pack in the lower right. As a result, a uniform flow of current is achieved by all the battery cells contained in the battery pack, thus avoiding a point overheating of individual battery cells by an uneven current distribution.

The connection structures are made of an electrically conductive material and are formed flat. Preferably, the connection structures cover the respective holding structures almost or completely. Due to the planar design of the connection structure, a uniform current distribution to all connected battery cells is made possible. The maximum current carrying capacity is defined by the cross-section of the connection structure and the respective area, ie by the volume required to conduct the current. Since more than a hundred battery cells are partially placed in such a battery pack and each battery cell can provide high currents for a short time, the respective connection structures must provide a sufficiently high current resistance, which corresponds to the sum of the individual currents of the individual battery cells. Ie. Over the connection structures flow in the charging and in particular in the discharge process with a maximum requirement of 100A. Preferably, the terminal structure is formed of a metal. Here is a use of copper. However, it is also possible to produce the connection structure from another electrically conductive material. The connection element, over which the connection is made from the connection structure to the electrical connection contact of the battery cell, is made of a second other metal, for example nickel or aluminum. Here is the use of a Hiluminbandes. However, it is also possible to use another electrically conductive material for the connection elements.

The connection structure has contact openings. In this case, each contact opening is associated with a connection opening of the holding structure. Preferably, the respective contact openings correspond to the associated connection openings, wherein it is also possible for the contact opening to be larger or smaller than the connection opening of the corresponding holding structure. Thus, the contact opening releases the respective connection opening of the holding structure and thus the electrical connection contact of the respective battery cell positioned underneath. Therefore, the connection structure can be contacted by means of the connection element through the connection opening into the receiving opening to the electrical connection contact of the battery cell. The connection openings may have any desired shapes, preferably they are essentially round like the contact openings.

The connection elements, which are preferably strip-shaped, are fastened to the connection structure by means of a joining method and protrude into the corresponding contact opening in each case. As a particularly advantageous connection method, friction welding or ultrasonic welding of the connection elements to the respective connection structure has proved successful, since with such a method a sufficient mechanical and also electrical connection between connection structure and connection element is achieved. The heat development during friction welding is much lower than in a spot welding process or a soldering process. Moreover, joining a thicker material to a thinner one is difficult to achieve a reliable mechanical and electrical connection with a spot welding process because the energy is absorbed by the thicker material. In friction welding, on the other hand, a surface connection is created in the materials to be joined to the respective surfaces. The two surfaces to be connected are moved under pressure relative to each other, whereby a heating and plasticization of the material occurs. The surfaces to be joined are then pressed together under high pressure. Thus, a reliable mechanical and electrical connection can be achieved even with the different material thicknesses and different materials.

Moreover, it is advantageous to prefabricate the connection structures with the correspondingly connected connection elements in such a way that they can be manufactured with the individual battery cells before the battery pack is assembled. After the connection structure with the connection elements fastened thereon, which respectively project into the contact openings, is placed on the respective support structure, the electrical connections between the positive and negative connection contacts of the respective battery cells can be established. Here, a spot welding or soldering is still possible to ensure a reliable electrical connection of the electrical connection of the battery cell with the connection elements.

The connecting element has a cross-section which melts at a current above a maximum charging or discharging current, whereby the connection between the connection structure and connecting element is interrupted and thus a further current flow is prevented. In addition, it can be prevented that a cell overheated in the event of a fault and with a corresponding chain reaction, the whole battery pack is disabled and dangerous situations can occur.

For thermal insulation, a heat-insulating layer can further be arranged between the connection structure and the support structure, for example made of Teflon. Preferably, the heat-insulating layer is formed with the same dimensions and openings as the terminal structure.

Through the cross section of the connecting element can be achieved when charging the battery pack, a uniform power distribution to the individual connected within the battery pack battery cells. When charging the battery pack, it is necessary to charge all battery cells of the battery pack evenly, i. with the same amperage and not, as in the prior art, the battery cells that are closer to the terminal portion of the battery pack to load more, as these would then heat excessively and could lead to uncontrollable reactions. Due to the inventive design of the battery pack and in particular by the connection structure and the connection elements fastened thereon, the charging current from the battery pack connection region is distributed evenly to all battery cells of the battery pack. By a selective selection or reduction of the cross section of the connection element, the amount of current flowing to the battery cell, or is removed from this, limited and distributed during charging on other battery cells. During discharging, the defined cross-section of the connection element ensures that in an uncontrolled discharge with a current flow above the specified maximum current of a battery cell, the connection element melts and is thus decoupled from the remaining battery pack.

Ie. the cross-section of the connecting element according to the invention provides a backup function when discharging the battery cells and a limiting function during charging.

In connections of the battery cells according to the prior art, the individual battery cells are usually connected via contact strips, in particular when charging the battery cells, which are close to the battery pack connection area, obtained a larger current than the battery cells, which are located away from the battery pack connection area. Thus, the battery cells arranged close to the battery pack connection region can heat up beyond a permissible temperature and cause a fault as described above.

Since the entire battery pack may be exposed to critical heat developments both during manufacture and during operation, the support structures may preferably be made of a temperature resistant non-electrically conductive material, preferably thermoset.

The receiving opening is dimensioned, i. in a round cell with its inner diameter, to the respective outer dimensions, i. the outer diameter of the respective battery cell adapted to thus achieve a corresponding clamping effect on the battery cell after inserting the battery cell in the receiving opening. Alternatively or additionally, a predetermined amount of adhesive can be introduced into the receiving opening in order to improve the fixation of the battery cell.

The outer dimensions of the connection structure essentially correspond to the outer dimensions of the support structure.

The holding together of the holding structures with the battery cells used or with the attachment structures located on the support structures is achieved primarily via the connection between the connection element and the connection structure or connection element and the electrical connection contact of the battery cell. However, in order to relieve this electrical connection as mechanically as possible, it may be advantageous to arrange a respective fastening element between the first and second holding structure in order to thus additionally hold the battery cells inserted into the holding structures firmly together between the first and second holding structures.

The connection element is attached to the connection structure at a connection point, preferably by means of friction welding or ultrasonic welding. The dimensions of the connection point can correspond in each case to the square area of the width of the connection element. By thus flat connection of the connection element with the connection structure a secure mechanical and an electrical connection is achieved.

The object is also achieved by a method for producing a battery pack. The method preferably comprises the steps of inserting at least two battery cells into a holding structure, connecting a connection structure to a connection element, wherein for each battery cell at least one connection element is provided on each connection structure. After connecting the connection element to the connection structure, the connection structure with the connection elements is correspondingly aligned so that the connection elements can be connected to the respective electrical connection contacts of the battery cells. Then the other side of the battery cells is analogously connected to the respective connection structure and the connection elements.

The individual features of the first embodiment can also be applied to the second embodiment and vice versa.

In the following, embodiments of the invention will be described in detail with reference to the accompanying figures.

In the figures show:

1 a perspective view of a battery pack according to the present invention.

2 a perspective view of a support structure.

3a a sectional view of a battery cell, which is incorporated in a battery pack according to the present invention.

3b a sectional view of a receiving opening or a connection opening of a support structure.

4 a representation of a connection structure from above.

5 an illustration of the battery pack according to another embodiment from above.

6 an enlarged view of an area 5 ,

7 a battery pack from the prior art.

8th shows a perspective view of a battery pack according to another embodiment of the invention.

9 shows a perspective view of a support structure according to another embodiment.

10 shows a sectional view of the battery pack according to the second embodiment of the invention.

1 shows a perspective view of a battery pack 10 , The battery pack 10 includes 40 battery cells in this embodiment 11 whose end faces each in holding structures 12 . 13 are included. The holding structures 12 . 13 are each of connection structures 14 covered, wherein the lower connection structure is not visible in this illustration. The connection structure 14 has contact openings 16 on. Next has the connection structure 14 connection elements 15 on that at the connection structure 14 are attached and in each case in the contact openings 16 protrude. The connection elements 15 are each about unspecified here connections with the electrical connection contacts of the battery cells 11 connected. The connection structure 14 has a battery pack connection area in its front left area 17 on top of the holding structure 12 protrudes. On the bottom is a battery pack connection area 18 to be recognized, differing from the lower connection structure 14 extends and also serves for connection to other battery packs or chargers or loads.

2 shows a perspective view of a support structure 12 . 13 , The holding structure 12 . 13 is in 2 shown from the recording side. The receiving side is the side where the respective receiving openings 21 are arranged. In the receiving openings 21 become the battery cells 11 used. The holding structure 12 . 13 is characterized in that preferably at least one bottom element or projection 22 in the receiving opening 21 protrudes and as a support for the battery cells used 11 serves. In the holding structure 12 . 13 according to 2 are four tabs 22 provided in the receiving opening 21 protrude. Another element, which is here recognizable, but not specified, is that of the receiving opening 21 opposite connection opening 23 , This is in 3b shown in detail. The connection openings 23 the holding structure 12 . 13 lie on the side, which is also called connection side.

In the 3a and 3b are sectional views of a battery cell 11 or the holding structures 12 . 13 with the connection structures 14 shown. According to 3a is a battery cell 11 in an upper and lower support structure 12 . 13 added. How out 3b can be seen, assigns each of the support structure 12 . 13 receiving openings 21 and connection openings 23 on. Thus, a battery cell 11 each with its front side in a receiving opening 21 used and the electrical connection contact of the battery cell 11 is then through the connection opening 23 reachable. The electrical connection contacts 33 and 34 the battery cell 11 lie below the top or bottom of the support structure 12 . 13 , That means the electrical connection contacts 33 and 34 lie deeper than the surfaces of the holding structures 12 . 13 , on each of which the connection structures 14 be hung up. According to 3b indicates the area in which the battery cell 11 is taken, projections 22 on, which may be formed as individual projections or may project as a circular flange or edge in the opening. The dimensions of the receiving openings 21 are the outer dimensions of the battery cells 11 customized. Over or on the support structures 12 and 13 are the connection structures 14 each disposed of a conductive electrical material. The connection structures 14 each have contact openings 16 on. Through these contact openings 16 become connection elements 15 led to the connection structure 14 Preferably, for example, by means of a joining process, for example friction welding or ultrasonic welding are attached. The connection element 15 thus extends into the contact opening 16 and is by means of a conventional bonding method, such as spot welding, soldering or the like. With the electrical connections 33 and 34 the battery cell 11 connected.

In 4 is a connection structure 14 in a view from above, the corresponding contact openings 16 having. The number of contact openings 16 corresponds to the number of batteries in the battery pack 10 contained battery cells 11 , The size of the contact opening 16 is sized so that a connecting element 15 through the contact opening 16 can be passed and with the electrical connection contacts 33 . 34 the battery cell 11 can be contacted. The connection structure 14 according to 4 also has a battery pack connection area 17 . 18 to be connected to the leads of chargers or loads. When combining several battery packs 10 The plurality of battery packs are respectively connected to their battery pack connection areas 17 . 18 connected with each other. In such a case, the individual connection structures 14 each designed for the total current of the interconnected battery pack.

5 shows a further embodiment of the battery pack according to the invention. In this embodiment, the connection elements 51 designed so that a connecting element 51 is strip-shaped and each in two adjacent contact openings 16 protrudes. This strip-shaped connecting element 51 is at the edge regions of the corresponding contact openings 16 each at a junction 52 with the connection structure 14 connected. The strip-shaped connection element 52 extends into the corresponding contact openings 16 and will from there with the electrical connection contacts 33 . 34 the corresponding battery cell 11 connected. As can be seen in this embodiment, lie on one side of the battery pack 10 each similar electrical connection contacts 33 . 34 ie either the positive or the negative terminals of the battery cells 11 ,

6 shows an enlarged view of an area 5 in which a connection structure 14 via a strip-shaped connection element 51 which is in two contact openings 16 protrudes, with the corresponding battery cells 11 connected is. From the battery cells 11 is for example the connection contact 33 to recognize, with this terminal contact 33 using solder joints or welds 53 with the strip-shaped connection element 51 connected is. The strip-shaped connection element 51 is in this embodiment by means of two connection points 52 with the connection structure 14 connected. In a further embodiment, it is possible, this strip-shaped connection element 51 in each case only at one connection point 52 with the connection structure 14 In order to connect to a more efficient and less complicated connection method between the connection structure 14 and the strip-shaped connection element 51 to get.

7 illustrates a conventional battery pack in which multiple battery cells 11 are connected in parallel. As it is easy to see from the illustration, the individual battery cells 11 directly with strip-shaped connection elements 71 and 72 interconnected, with the connection points 73 both the connection between the cross connections 72 and the longitudinal connections 71 as well as the underlying electrical connection contact 33 the battery cell 11 serve. Thus, the heat that results in the connection of transverse and longitudinal joints 71 and 72 occurs, also directly on the underlying connection contact 33 passed, leaving the battery cell 11 also exposed to this heat during the assembly process. By too much heat can also be the insulation 35 the battery cell 11 to be damaged.

When connecting the battery cells 11 as in 7 large heat effects occur on the battery cells 11 and can lead to dangerous situations. In addition, in the event of a failure of a battery cell 11 These will lead to a failure of the entire battery pack as it may cause the cross-link to melt 72 or the longitudinal connection 71 comes. This is the responsible for the high current battery cell 11 not reliable from the other battery cells 11 separated, so that it can lead to dangerous chain reactions and ultimately several battery cells 11 outgas and explode.

When charging a battery pack according to 7 become the battery cells 11 , which are powered on the power supply side more power than a connection structure 14 according to the present invention. About the strip-shaped transverse and longitudinal connections 71 and 72 no reliable distribution of the supplied power is possible. Consequently, the battery cells located on the power supply to heat 11 stronger than the battery cells 11 that are further away from the power supply.

Another advantage of the embodiment of the invention results from the thermal decoupling of connection structure 14 and connection contact 33 . 34 the battery cell 11 , By the distance between the connection structure 14 and the connection contact 33 . 34 as it is good in 3a can be seen, a heat can be due to a high current flow in the connection structure 14 or by making the connection at the junction 52 between connection element 51 and connection structure 14 not on the battery cell 11 transfer. The distance can be over the projections 22 or the edge of the support structures 12 . 13 to adjust. That is, for large battery packs with many battery cells 11 and consequently a high current on the connection structure 14 can be a holding structure 12 . 13 be used, in which the at least one projection 22 thicker than in a support structure 12 . 13 for a few battery cells 11 is designed. Consequently, the battery cell becomes 11 spared from the resulting from this heat stress and only the heat in the connection between connection element 15 . 51 and connection contact 33 . 34 exposed and the heat through its own current flow.

The size of the battery pack according to the invention can be varied as desired by the choice of the number of battery cells. In addition, the shape of the battery pack can be adjusted by the number and arrangement of the battery cells to the particular application. If, for example, several interconnected battery packs are used in a vehicle, if one or more battery cells fail, it is possible to replace only the battery pack with the failed battery cells, which leads to substantial economic advantages.

8th shows a battery pack according to the invention according to a second embodiment of the present invention.

The battery pack 10 consists of two connection structures 14 together. Next are two holding structures 12 and 13 intended. The battery cells 11 are each in receiving openings not shown 21 the holding structures 12 . 13 used or added to this. The connection structures 14 on both outward surfaces of the support structures 12 and 13 rest, are formed similarly as the terminal structures of the first embodiment.

Unlike in the first embodiment, the connection elements 15 but here between the downward surface 24a the upper connection structure 14 and the upward surface 24 the first holding structure 12 arranged or for in 8th bottom connection structure 14 , are the connection elements 15 arranged on the upwardly directed side. This has the advantage that the connection elements 15 , which are preferably made of a nickel or hilium band, do not have to be bent as much as in the first embodiment.

In the production of the battery pack 10 can thus in two separate or parallel operations on the one hand, the battery cells 11 in the holding structures 12 . 13 be used and for example with the fasteners 25 held together. Parallel to this, the connection structures can be arranged 14 with the contact openings 16 and connection elements 15 manufacture, wherein the connection elements 15 are each arranged so that they are in the associated contact opening 16 protrude. The connection between the respective connection element 15 and the connection structure 14 is produced analogously to the first embodiment by friction welding or by ultrasonic welding. After all connection elements 15 at the connection structure 14 are attached, the connection structure 14 turned over and on the upward or outward facing surface 24 the holding structure 12 respectively. 13 placed. In addition, between the holding structures 12 respectively. 13 and the respective connection structure 14 an insulating layer are introduced.

The holding together of the holding structures 12 respectively. 13 by means of the fastening elements 25 is not mandatory, but it is characterized in particular the manufacturing process of the battery pack 10 easier and safer. If necessary, it may also be sufficient, both during the manufacturing process and when using the battery pack 10 the clamping effect between battery cells 11 and receiving openings 21 to use such that the holding structures 12 respectively. 13 be held together sufficiently.

After the connection structure 14 with the connection elements 15 on the prefabricated battery pack 10 consisting of the battery cells 11 and the two support structures 12 and 13 , is placed or hung up, the connection structure 14 with other fasteners 26 each at one of the support structures 12 . 13 be attached. It is also possible a fastener through the battery pack 10 through and on the opposite sides of the connection structures 14 screw together. This will make the connection structure 14 with the connection elements 15 in terms of holding structures 12 and 13 and the battery cells received therein 11 fixed. Now, in another method, the electrical connection between the respective connection elements 15 and the positive and negative electrical contacts 33 . 34 the battery cell 11 getting produced. The provision of fasteners 26 is not mandatory. Depending on the application, ie, for example, if little mechanical stress such as vibrations and the like on the battery pack 10 act, is sufficient for the fixation of the connection structures, the connection between the connection elements 15 and the connection contacts 33 . 34 the battery cells 11 ,

Such an arrangement of the connection element 15 between the connection structure 14 and the support structure 12 . 13 or the electrical connection contact 33 respectively. 34 has the advantage that the connecting element 15 only minimal mechanically kinked must. This allows the connection elements 15 when producing the friction-welded connection or ultrasonic friction welding connection simply in the region of the contact points 52 next to the corresponding contact opening 16 be launched and with the connection structure 14 get connected. After then all connection elements 15 with the connection structure 14 are connected, the connection structure 14 turned over so that the connecting elements 15 between the holding structure 12 . 13 and the connection structure 14 lie and thus almost directly on the electrical contacts 33 . 34 the battery cell 11 rest. Then the other electrical connection at the electrical connection contact 33 . 34 the battery cell 11 getting produced. As the connecting element 15 no longer needs to be bent so much as in the first embodiment, the electrical connection can be made more reliable and there are fewer contact errors. In addition, there are no negative forces acting on the connection tensile forces, which by restoring forces of strongly bent connection elements 15 to be triggered.

Another advantage that results from this embodiment is that in the mechanical load during operation of the battery pack, for example by the occurrence of vibration, the connection elements 15 less under mechanical tension and thus breaking the contact between a connecting element 15 and the electrical connection contacts 33 respectively. 34 the battery cell 11 In addition, an important advantage is that in this embodiment, the connection points between connecting elements 15 and connection structures 14 are protected against external influences, which may be of a mechanical nature, for example. It also creates a battery cells 11 remote completely flat surface, which in particular significantly facilitates the attachment of a cover sheet or a coating.

9 shows an alternative embodiment of the support structures 12 respectively. 13 , The alternative embodiment of the support structure 12 . 13 points in contrast to the holding structure in 2 a circumferential flange 27 on top of the boundary of the receiving opening 21 for the inserted battery cell 11 forms. The opening with the smaller diameter, located inside the flange 27 extends, is the connection opening 23 and the opening, in the illustration according to 9 is directed upwards and a larger diameter than the connection opening 23 has, is the receiving opening 21 ,

The production of the support structure 12 . 13 according to 9 is compared to the holding structure according to 2 easier. So can the holding structures 12 . 13 with receiving opening 21 and connection opening 23 be produced in a simplified injection molding process or machined very economically.

10 shows a sectional view of the battery pack 10 according to 8th , A battery cell 11 is between the first and second support structures 12 and 13 inserted and used by the respective receiving openings 21 held. The inwardly projecting flange 27 is not shown here, but protrudes over the upper or lower end edge of the battery cell 11 in the respective opening of the support structure 12 . 13 , The positive and negative electrical connection contacts 33 and 34 lie within the support structure 12 . 13 and are thus against premature contact when placing the connection structures 14 protected. The connection structure 14 has contact openings 16 on, with the connecting elements 15 in this contact opening 16 protrude. The connection element 15 Here is much less kinked or mechanically deformed as in the embodiment according to 3A , Next shows the 10 a first fastening element 25 which the first and second support structure 12 and 13 with the inserted battery cells 11 holds together. For this purpose, two screws in each holes in the support structures 12 . 13 introduced and each engage in a thread of a sleeve 25 one. Next is another fastener 26 shown which the connection structures 14 with the support structures 12 . 13 screwed.

For the fasteners 25 . 26 this is a measure to be taken depending on the application. So there are applications where these fasteners 25 . 26 can be omitted and there are applications where only one or the other fastener 25 respectively. 26 or both fasteners 25 . 26 can be used. In particular, it is for the choice of the use of fasteners 25 . 26 The decisive factor is whether and, if so, which external influences the battery pack 10 is exposed.

In one embodiment, a battery pack includes:
at least two battery cells ( 11 ), each battery cell ( 11 ) each have a positive and a negative electrical connection contact ( 33 . 34 ) having,
wherein the electrically positive terminal contacts ( 33 ) of the battery cells ( 11 ) a first connection structure ( 14 ) and the electrically negative terminal contacts ( 34 ) of the battery cells ( 11 ) a second connection structure ( 14 ) and each connection structure ( 14 ) has a current strength equal to the sum of the individual currents of each connected battery cell ( 11 ), wherein each battery cell via at least one connection element ( 15 . 51 ) with the first connection structure ( 14 ) and via at least one further connecting element ( 15 . 51 ) with the second connection structure ( 14 ), wherein a cross section of the respective connecting element ( 15 . 51 ) to a predetermined maximum current of a battery cell ( 11 ) is adjusted.
In particular, the at least two battery cells ( 11 ) connected in a parallel circuit, in which each positive and negative electrical connection contacts ( 33 . 34 ) each one connection structure ( 14 ) assigned.
In particular, the battery pack ( 10 ) at least one holding structure ( 12 . 13 ) for receiving the at least two battery cells ( 11 ).
In particular, the at least two battery cells ( 11 ) designed as round cells.
In particular, the electrical connection contacts ( 33 . 34 ) of the battery cell ( 11 ) on opposite end faces of the battery cell ( 11 ) arranged.
In particular, a first holding structure ( 12 ) on the side of the positive electrical connection contacts ( 33 ) and a second holding structure ( 13 ) on the Side of the negative electrical connection contacts ( 34 ) arranged.
In particular, the holding structure ( 12 . 13 ) Receiving openings ( 21 ) for receiving at least part of the outer shape of each battery cell ( 11 ) of the battery pack.
In particular, each receiving opening ( 21 ) to a predetermined depth for the spatial fixation of the battery cell.
In particular, the arrangement of the receiving openings ( 21 ) in the support structure ( 12 . 13 ) each one distance between the battery cells ( 11 ) of the battery pack, which in the receiving openings ( 21 ) are used.
In particular, the holding structure ( 12 . 13 ) Connection openings ( 23 ) for each battery cell ( 11 ) of the battery pack ( 10 ), wherein the connection openings ( 23 ) in each case an electrical contact in the receiving openings ( 21 ) used battery cells ( 11 ) enable.
In particular, the receiving opening ( 21 ) greater than an associated connection opening ( 23 ).
In particular, the holding structure ( 12 . 13 ) each have a receiving side for receiving the battery cells ( 11 ) and a connection side for an electrical connection of the battery cells ( 11 ), wherein the receiving side of the connection side is opposite.
In particular, the connection openings ( 23 ) of the support structure ( 12 . 13 ) arranged on the connection side.
In particular, the first connection structure ( 14 ) with electrically positive connection contacts ( 33 ), the second connection structure ( 14 ), which are connected to the electrically negative connection contacts ( 34 ), opposite.
In particular, the first connection structure ( 14 ) on the terminal side of the first support structure ( 12 ) and the second connection structure ( 14 ) on the terminal side of the second support structure ( 13 ) and the battery cells ( 11 ) are between the first holding structure ( 12 ) and the second support structure ( 13 ) arranged.
In particular, each connection structure ( 14 ) a battery pack connection area ( 17 . 18 ) on.
In particular, the battery pack connection area ( 17 . 18 ) over an outer edge of the respective support structure ( 12 . 13 ).
In particular, two battery pack connection areas ( 17 . 18 ) located diagonally opposite the battery pack ( 10 ) are arranged.
In particular, each connection structure ( 14 ) made of an electrically conductive material and formed flat, to a uniform current distribution to all connected battery cells ( 11 ).
In particular, the connection structure ( 14 ) formed of a first metal, preferably of copper, or another electrically conductive material.
In particular, the connection element ( 15 . 51 ) made of a second metal, preferably made of nickel strip (Hiluminband) or other electrically conductive material.
In particular, the connection structure ( 14 ) Contact openings ( 16 ), each of the connection openings ( 23 ) a holding structure ( 12 . 13 ) assigned.
In particular, the contact openings ( 16 ) of the connection structure ( 14 ) each of the connection openings ( 23 ) of the support structure ( 12 . 13 ) and a corresponding contact area of the positive or negative terminal contact ( 34 . 33 ) of the battery cell ( 11 ) free.
In particular, the connecting elements protrude ( 15 . 51 ), in each case by means of a joining method to the connection structure ( 14 ), in the respective contact openings ( 16 ) into it.
In particular, the connection elements ( 15 . 51 ) by friction welding or ultrasonic welding to the connection structure ( 14 ) attached.
In particular, the connection element ( 15 . 51 ) at the electrical connection contact ( 34 . 33 ) of the battery cell ( 11 ) connected by means of a material connection.
In particular, the connection element ( 15 . 51 ) at the electrical connection contact ( 33 . 34 ) of the battery cell ( 11 ) connected by spot welding or soldering.
In particular, the connection element ( 15 . 51 ) has a cross-section which melts at a current above a maximum charge or discharge current and the connection between the connection structure ( 14 ) and electrical connection contact ( 33 . 34 ) of the battery cell ( 11 ) interrupts.
In particular, between connection structure ( 14 ) and terminal side of the support structure ( 12 . 13 ) a heat-insulating layer, preferably made of Teflon arranged.
In particular, the cross section of the connecting element ( 15 . 51 ) are designed so that when charging in the battery pack ( 10 ) connected battery cells ( 11 ) an even current distribution takes place.
In particular, the holding structure ( 12 . 13 ) of a temperature-resistant and electrically non-conductive material, preferably thermosetting plastic, formed.
In particular, the receiving opening ( 21 ) in their dimensions to the outer periphery of the male battery cell ( 11 ) and exerts a clamping effect on the battery cell ( 11 ) out.
In particular, the outer dimensions of the connection structure ( 14 ) substantially the outer dimensions of the support structure ( 12 . 13 ).
In particular, the connection structure ( 14 ) Connection points ( 52 ) for the respective attachment of the connection elements ( 15 . 51 ), whose dimensions in each case at least the square area of the width of the connecting element ( 15 . 51 ) correspond.
In particular, between the first and second support structure ( 12 . 13 ) at least one fastener arranged to the two support structures ( 12 . 13 ) with the inserted battery cells ( 11 ).
In particular, the battery cells ( 11 ) in the receiving openings ( 21 ) fixed by means of an adhesive.
Furthermore, a method for producing a battery pack is specified, comprising: inserting at least two battery cells ( 11 ) into a holding structure ( 12 . 13 ), Connecting a connection structure ( 14 ) with a connection element ( 15 . 51 ) per battery cell ( 11 ), Connecting the connection elements ( 15 . 51 ) connected to the connection structure ( 14 ), with electrical connection contacts ( 34 . 34 ) of the battery cell ( 11 ).

Claims (10)

Battery pack comprising: - at least two battery cells ( 11 ), each battery cell ( 11 ) a positive and a negative electrical connection contact ( 33 . 34 ), - wherein at least the electrically positive terminal contacts ( 33 ) or the electrically negative terminal contacts ( 34 ) of the battery cells ( 11 ) a connection structure ( 14 ), each battery cell ( 11 ) via at least one connecting element ( 15 . 51 ) with the connection structure ( 14 ), wherein a cross section of the respective connecting element ( 15 . 51 ) to a predetermined maximum current of a battery cell ( 11 ), - the connecting element ( 15 . 51 ) at one of the battery cells ( 11 ) facing side of the connection structure ( 14 ) is attached. Battery pack according to claim 1, wherein the electrically positive terminal contacts ( 33 ) of the battery cells ( 11 ) a first connection structure ( 14 ) and the electrically negative terminal contacts ( 34 ) of the battery cells ( 11 ) a second connection structure ( 14 ), wherein the connection elements ( 15 . 51 ) on the sides of the connection structures ( 14 ) attached to the battery cells ( 11 ) are facing. Battery pack according to claim 1 or 2, further comprising at least one support structure ( 12 . 13 ) for receiving the at least two battery cells ( 11 ). Battery pack according to one of claims 1 to 3, wherein the support structure ( 12 . 13 ) an area ( 24 ), which are connected to the connection structure ( 14 ), the area ( 24 ) of connection openings ( 23 ) is broken. Battery pack according to one of claims 1 to 4, wherein the connection structure ( 14 ) in the assembled state on the surface ( 24 ) of the support structure ( 12 . 13 ) rests, and the connection elements ( 15 . 51 ) the connection opening ( 23 penetrate). Battery pack according to one of the preceding claims, wherein a first support structure ( 12 ) on the side of the positive electrical connection contacts ( 33 ) and a second holding structure ( 13 ) on the side of the negative electrical connection contacts ( 34 ) is arranged. Battery pack according to one of the preceding claims, wherein between the first and second support structure ( 12 . 13 ) at least one fastening element ( 25 ) is arranged around the two support structures ( 12 . 13 ) with the inserted battery cells ( 11 ). Battery pack according to one of the preceding claims, wherein at least one fastening element ( 26 ) is provided to the two connection structures ( 14 ) with which the battery cells ( 11 ) receiving support structures ( 12 . 13 ). Battery pack according to claim 7 or 8, wherein the fastening element ( 25 . 26 ) is formed of electrically non-conductive material or surrounded by an electrically insulating material. Method for producing a battery pack, comprising the steps: - inserting at least two battery cells ( 11 ) into a holding structure ( 12 . 13 ), - connecting a connection structure ( 14 ) each having a connection element ( 15 . 51 ) per battery cell ( 11 ), - placing the connection structure ( 14 ) with the attached connection elements ( 15 . 51 ) on the support structure ( 12 . 13 ), wherein the connection elements ( 15 . 51 ) on a side of the connection structure facing the battery cells ( 14 ), - connecting the connection elements ( 15 . 51 ) connected to the connection structure ( 14 ), with electrical connection contacts ( 34 . 34 ) of the battery cell ( 11 ).

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