Battery pack

Abstract

The invention relates to a battery pack (100) comprising a plurality of battery cells; a battery pack control device (300) which preferably comprises a printed circuit board (301); at least one cell connector (114, 115) for electrically connecting the battery cells; a first and second cell holder (101, 102), said first and second cell holder (101, 102) each forming a first and second receiving space (108, 109) for a first end region (201) and a second end region (202), which lies opposite the first end region, of each battery cell; a casing element (103) which surrounds the entire outer circumference of the battery cells preferably without a gap, said casing element (103) having a first end region (104) and bridging the distance (118) between the first and second cell holder (101, 102) when viewed in the longitudinal direction of the battery cells; and first connection means (106) and optionally second connection means (107), which can be designed as snap connections, in the region of the first cell holder (101) and the second cell holder (102), respectively, and in the region of the first end region (104) and the second end region (105) of the casing element (103), respectively.

Description

[0001] Battery pack

[0002] The present invention relates to an advantageous battery pack with a plurality of battery cells, which is preferably used in e-bikes, power tools, robots or in garden care technology.

[0003] Printed state of the art

[0004] DE 10 2021 206 822 A1 describes a battery pack with a cell holder consisting of several hard plastic components that are connected to one another via a connecting screw running in the longitudinal direction of the battery cells and form individual cell receptacles. All cell connectors are arranged on the outside of the cell holders on one side of the battery pack and are directly connected to a circuit board via a press-fit connection. In addition to the hard plastic components, the cell holder also has tolerance compensation elements, which are made, for example, of a soft plastic. The tolerance compensation elements are designed to clamp the battery cells in the individual cell receptacle.

[0005] DE 102016203431 A1 discloses a battery pack for a handheld power tool whose cell holder has sleeve-like insulating walls corresponding to the battery cells, with cylindrical cell openings located therebetween. The insulating walls are designed to prevent electrical contact between the battery cells. The battery cells are pressed into the cell openings. The cell holder is designed as a second housing component, with a first housing component being placed like a lid on the second housing component, enclosing a printed circuit board. Cell connectors for electrically interconnecting the battery cells are provided on the end faces of the battery cells. The battery pack also has two opposite side components positioned on the end faces of the battery cells.In the assembled state, these hold the first housing component and the second housing component together in such a way that detachment of the first housing component from the second housing component, or vice versa, is prevented.

[0006] Battery packs according to the aforementioned publications allow only a low degree of automation during assembly. Furthermore, they require a large number of complexly shaped individual parts, which increases production costs.

[0007] Object of the present invention

[0008] The object of the present invention is to provide a battery pack which avoids the aforementioned disadvantages.

[0009] Solution to the task

[0010] The above object is achieved by a battery pack according to the features of claim 1. Advantageous embodiments of the present invention are claimed in the dependent claims.

[0011] The battery pack according to the invention comprises a casing element which completely surrounds the battery cells, preferably without a gap, over their outer circumference, wherein the casing element has a first and a second end region and, viewed in the longitudinal direction of the battery cells, bridges a distance between a first and a second cell holder. The first and second cell holders thus adjoin the first and second end regions of the casing element and together complete a receiving space for the respective battery cell. Because the battery pack comprises first connecting means in the region of the first cell holder and the first end region of the casing element, the first cell holder and the casing region can be easily and automatically connected to one another with a comparatively simple geometric component shape, whereby part of a receiving space for the respective battery cell can be created.

[0012] According to one embodiment of the invention, the casing element has a second end region, with second connecting means being provided in the region of the second cell holder and the second end region of the casing element. This also allows a correspondingly advantageous automated connection to be made at the second end region of the casing element. This also makes it possible to produce a battery pack for contacting both end faces of the battery cells using cell connectors with simplified automation.

[0013] According to one embodiment of the invention, the first and / or second connecting means can be configured such that a connection by means of the first or second connecting means is automatically activated by longitudinally joining the first or second cell holder and the casing element. This allows for an increase in the degree of automation, since the provision and positioning of the components is simple, and only a translational movement is required to activate the connection.

[0014] According to one embodiment of the invention, the first and / or second connecting means may be snap-connecting means.

[0015] According to one embodiment of the invention, the first and / or second connecting means may comprise a preferably annular, movable snap-in catch and a run-up slope for the snap-in catch.

[0016] According to one embodiment of the invention, the first and / or second connecting means can be arranged in the respective side region of the first and second cell holders as well as in the side region of the casing element, preferably on both sides and / or opposite one another. This allows for space-saving accommodation of the connecting means, thereby improving the compactness of the battery pack. According to one embodiment of the invention, the casing element can be constructed in one piece from individual, adjacent hollow cylinders or hollow cylinder sections, with each hollow cylinder or hollow cylinder section enclosing a central circumferential region of a battery cell. Such a component ensures a comparatively simple shaping process in terms of manufacturing technology.In addition, such a design ensures a gusset-shaped recess in the lateral outer area between two adjacent hollow cylinders and thus an advantageous accommodation space for the accommodation of functional parts.

[0017] According to one embodiment of the invention, in particular the first and / or second connecting means can be accommodated completely or at least partially (e.g. the run-up slope or the snap) in each case in a lateral recess formed by two adjacent hollow cylinders.

[0018] According to one embodiment of the invention, the first and / or second cell holder can be an injection-molded part that at least partially encloses a cell connector, in which the cell connector is at least partially overmolded. This eliminates cabling and additional connection points.

[0019] According to one embodiment of the invention, the circuit board of the battery pack control device (also called “Battery Management System” or “BMS” for short or “Gel Management System” or “CMS” for short) can be positioned laterally along the battery pack.

[0020] According to one embodiment of the invention, the cell connector can have at least one press-fit pin, which enables a press-fit connection with the circuit board of the BMS. Via the press-fit connection, the BMS or CMS can record the State of Health (SOH) and / or State of Charge (SOC) of the battery cells and / or determine voltage differences for cell balancing and / or measure the temperature using a temperature sensor (e.g., NTC). For this purpose, the press-fit pins are provided with a single pin. However, press-fit pins with two pins can also be provided. These serve to transmit power. However, press-fit pins with more than two pins can also be provided depending on the specific requirement. According to one embodiment of the invention, part of the cell connector can be accommodated in a lateral recess formed by two adjacent hollow cylinders of the casing element.In particular, the part can be a tab of the cell connector, which connects the contact area of ​​the cell connector to the terminal of a battery cell and the connection area, e.g., the respective press-fit pin, of the cell connector on the circuit board. The area of ​​the cell holder in which the cell connector or the tab is overmolded can also extend into the area of ​​the recess. This also promotes compactness. Furthermore, the mechanical stability of the battery pack can be further improved.

[0021] On the opposite side of the casing element, at least one stiffening rib, preferably a plurality of stiffening ribs, can be provided in the region of the respective recess. This contributes to the mechanical stiffening of the battery pack.

[0022] According to one embodiment of the invention, the casing element can include a cooling function. The casing element allows heat generated in the battery cell to be dissipated to the outside of the battery pack. Due to the design according to the invention, heat generated in the battery cell with a cooling casing element can be radiated essentially radially outward into the area between the first and second cell holders, effectively preventing overheating of the battery pack.

[0023] According to one embodiment of the invention, the casing element can be made of a thermally conductive plastic material for this purpose. This can preferably be a plastic compound comprising a plastic material and filler material, wherein the thermal conductivity of the filler material is higher than that of the plastic material without filler material. For example, the filler material can be glass fibers.

[0024] According to one embodiment of the invention, the plastic compound material can have a thermal conductivity A of at least 0.5 W / mK, preferably of at least 1.0 W / mK, particularly preferably of at least 2.0 W / mK. According to one embodiment of the invention, a first cell connector can be arranged at the first end region and a second cell connector at the opposite second end region of the battery cell, the first cell connector can be fed to the circuit board from its first side and the second cell connector can be fed to the circuit board from its second side opposite the first side and can be electrically contacted with the circuit board, preferably via the aforementioned press-fit pins.

[0025] In addition, retaining projections can be provided on the respective cell holder, which serve as bearing points and / or for positioning the circuit board and / or as fastening points for the circuit board. Preferably, a clamp or snap connection can be applied between the respective retaining projection and the circuit board.

[0026] From a production and cost perspective, it is particularly advantageous if the first and second cell holders and / or the first and second cell connectors have an identical shape. This allows uniform shapes to be used for the cell holders and / or the cell connectors.

[0027] Description of the invention using an embodiment

[0028] An example of a practical embodiment of the present invention is described in more detail below with reference to the accompanying drawings. For the sake of clarity, identical, recurring features are provided with a corresponding reference numeral only once. They show:

[0029] Fig. 1 is an exploded view of the components of an example of a battery pack according to the invention without showing battery cells;

[0030] Fig. 2 a side view of the completed battery pack of Fig. 2 without housing;

[0031] Fig. 3 is a sectional view along the section plane AA in Fig. 2; Fig. 4 is an enlarged view of the area B of Fig. 3;

[0032] Fig. 5 is a view of the section plane CC of Fig. 2; and

[0033] Fig. 6 is a view of the rear side of the casing element and the first and second cell holders of Fig. 1.

[0034] Fig. 1 shows the individual components of an example of a battery pack 100 according to the invention in an exploded view, omitting the battery cells. The battery pack 100 comprises a housing formed from a first housing shell 400 and a second housing shell 401. The housing can be designed differently depending on the intended use of the battery pack. The battery pack 100 further comprises a casing element 103, which is formed in one piece and comprises a plurality of hollow cylinders 112 or hollow cylinder sections arranged in a row. Due to the shape of the hollow cylinders 112 or hollow cylinder sections, a gusset-shaped recess 113 is formed on the casing element 103 in the respective contact area thereof. The casing element 103 has a first end region 104 and a second end region 105 opposite the first end region 104.

[0035] The casing element 103 encompasses a given number of battery cells (not shown) corresponding to the number of hollow cylinders 112 and ensures a cooling function, i.e. a function that enables heat occurring in the area of ​​the respective battery cell to be dissipated to the outside. For this purpose, the casing element 103 can be made from a plastic material and a plastic compound material comprising a filler material (e.g. glass fibers). In particular, the casing element 103 is an injection-molded part. The thermal conductivity of the filler material is higher than the thermal conductivity of the pure plastic material. The plastic compound material can have a thermal conductivity A of at least 0.5 W / mK, preferably of at least 1.0 W / mK, particularly preferably of at least 2.0 W / mK.

[0036] The casing element 103 is connected at its first end region 104 by a first

[0037] Cell holder 101 and, at its second end region 105, a second cell holder 102, each of which has a first cylindrical receiving space 108 and a second cylindrical receiving space 109, thereby forming receiving spaces for battery cells. The first and second cell holders 101, 102 preferably have an identical shape.

[0038] Between the casing element 103 and the first cell holder 101 or second cell holder 102, first connecting means 106 and second connecting means 107 are provided, which allow the casing element 103 to be mechanically and firmly connected to the first cell holder 101 and the second cell holder 102. The first and second connecting means 106, 107 are preferably designed such that a connection can be automatically activated by joining the first or second cell holder 101, 102 and the casing element 103 together in the longitudinal direction of the respective battery cell. This can significantly improve the degree of automation in production.

[0039] Preferably, the first and second connecting means 106, 107 can be snap-in connection means. An example of a snap-in connection is shown in Fig. 1. Here, the first and second cell holders 101, 102 have a plurality of annular snap-in catches 110. Furthermore, projections corresponding to the snap-in catches 110 and having a run-up slope 111 are provided on the first and second end regions 104, 105 of the casing element 103. As a result, the respective snap-in catch 110 is initially bent outward by means of the run-up slope 111 during the assembly process and then, due to its elasticity, snaps over the respective projection, thereby establishing a mechanical connection.

[0040] The first and second connecting means 106, 107 are each arranged on both sides of the casing element 103 or the cell holders 101, 102, respectively, viewed in the longitudinal direction of the battery cells. They are located within the respective recess 113 and thus support a space-saving design of the battery pack 100 according to the invention. The connecting means 106, 107 can be located entirely or at least only partially in the respective lateral recess 113. On the upper or lower end face of the respective cell holder 101, 102 there is a bore 125 through which the electrical connection of the respective battery cell protrudes, so that it can be contacted by a first cell connector 114 in the region of the first cell holder 101 or by a second cell connector 115 in the region of the second cell holder 102.

[0041] The first cell connectors 114 and second cell connectors 115 each have a contact area that contacts the respective electrical connection (terminal) of the battery cell, from which a first tongue 119 and a second tongue 120 extend, approximately at a right angle, along the battery cells, at the end of which, opposite the contact area, a first press-fit pin 116 and a second press-fit pin 117 are connected for a press-fit connection to a circuit board 301. The first press-fit pin 116 has only one pin and serves to enable the BMS or CMS, for example, to detect the state of health (SOH) and / or the state of charge (SOC) of the battery cells and / or to determine voltage differences for cell balancing and / or to measure the temperature using a temperature sensor (e.g., NTC) (not shown in the figures).The second press-fit pin 117, which comprises two pins, serves to transmit electrical power to the circuit board 301 or the battery pack control device 300. For this purpose, the press-fit pins 116, 117 protrude approximately at a right angle from the respective tongue 119, 120 of the respective cell connector 114, 115 in the direction of the circuit board 301. The respective press-fit pin 116, 117 is pressed onto the circuit board 301 and in doing so passes through a complementarily formed through-opening 303 of the circuit board 301, simultaneously establishing electrical contact with the circuit board 301, i.e., the conductor tracks located thereon. This not only increases the degree of automation during production, but also eliminates the need for cable connections and soldered connections.

[0042] In addition, first and second retaining projections 126, 127 can be provided on the side region of the first and second cell holders 101, 102, respectively, which serve as bearing points and / or for positioning the circuit board 301 and / or as fastening points for the circuit board 301. The first and second retaining projections 126, 127 extend outward at a right angle relative to the longitudinal axis of the battery cells. Preferably, a clamping or snap-in connection can be applied between the respective retaining projection 126, 127 and the circuit board 301. In the case of a locking connection, the first and second retaining projections 126, 127 can, for example, engage in a locking manner in an associated bore 304 in the circuit board 301.

[0043] The circuit board 301 carries a battery pack control device 300 (not shown in Fig. 1), which is the "Battery Management System" (BMS) or the "Gel Management System" (CMS). Furthermore, terminals 305 are provided on the circuit board for power or signal tapping. The terminals 305 are preferably also fixed to the circuit board 301 via press-fit pins arranged at the base of the respective terminal 305.

[0044] The first and second cell connectors 114, 115 can be at least partially overmolded in the first cell holder 101 and the second cell holder 102, respectively. The first and second cell holders 101, 102 then each form an injection-molded part that at least partially encloses the cell connectors 114, 115.

[0045] Fig. 2 shows a side view of the battery pack 100 according to Fig. 1 in the assembled state, with the housing omitted. Fig. 2 shows that the first and second connecting elements 106, 107 are each located in the region of the gusset-shaped recess 113. Fig. 2 also shows the position of the first and second press-fit pins 116, 117. The press-fit pins 117, each having two pins, are laterally offset from the respective connecting element 106, 107, whereas the press-fit pins 116, each having only one pin, are arranged in the same orientation as the connecting elements 106, 107, i.e., in the region of the respective recess 113.

[0046] The double-formed press-fit pins 117 are intended to transmit electrical power. The single-formed press-fit pins 116, on the other hand, are intended to transmit only one signal, e.g., a signal relating to the State of Health (SOH) and / or the State of Charge (SOC), to the battery pack control device 300 or the circuit board 301. Only a small area of ​​the respective tongue 119, 120 of the first or second cell holder 101, 102 is exposed, whereas the much larger area is overmolded in the first cell holder 101 or second cell holder 102. Fig. 3 shows a sectional view of the battery pack 100 of Fig. 2 in the sectional plane AA. From Fig. 3 it can be clearly seen how the respective snap 110 engages around the projection formed with the run-on bevel 111 and ensures a mechanical fixation of the first and second cell holder 101, 102 to the first and second end region 104, 105 of the casing element 103.In this assembled state, the first and second cell holders 101 are located.

[0047] 102 at a distance 118 from each other, which is determined by the length of the jacket element

[0048] 103. Due to the cooling effect of the casing element 103, heat W can be dissipated radially outwardly from the individual battery cells located in the first and second receiving spaces 108, 109 and the casing element 103. As is further clear from Fig. 3, the laterally projecting first and second press-fit pins 116, 117, together with the first and second retaining projections 126, 127 of the first and second cell holders 101, 102, form a uniform mounting base for the circuit board 301 of the battery pack control device 300.

[0049] As shown in Fig. 4 (omitting the first retaining projections 126) as an example for the first cell holder 101, only a small area of ​​the first tongue 119 of the first cell connector 114 is not covered by the material of the first cell holder 101. The second cell holder 102 is designed accordingly. The right-angled area of ​​the first tongue 119 carries at its end the first press-fit pin 116, which is pressed into a through-opening 303 in the circuit board 301 (see Fig. 2) and ensures secure contact with the wiring (not shown) of the circuit board 301. Thus, the first and second cell connectors 114, 115 are positioned via the first and second cell holders 101, 102 in the side area of ​​the battery pack 100 for assembly with the circuit board 301.

[0050] According to Fig. 5, the first cell connectors 114 each have a first connection tab 122 and a second connection tab 123 separated from the first connection tab 122 by a slot 124. In this area, a weld is made to the connection terminal of the respective battery cell. The first tongue 119 of the first cell connector 114 is accommodated in an area 121 of the first cell holder 101, which is located in or near the gusset-shaped recess 113. The second cell connectors 115 at the opposite end of the battery pack, as well as the opposite second cell holder 102, are designed accordingly. There, the order of the cell connectors 114, 115 and the press-fit pins 116, 117 is merely reversed due to the wiring of the battery cells.

[0051] The embodiment shown in the figures is a five-cell battery pack in which the battery cells are interconnected in a so-called "5S 1 P circuit." This means that five cells are connected in series and, due to the opposing poles of the battery cells, are also connected in parallel.

[0052] Fig. 6 shows the rear side of the cell holders 101, 102 and the casing element 103. At least one, preferably a plurality of, stiffening ribs 128 can be provided on the rear side in the region of the respective recess 113 to stiffen the casing element 103. The respective projections equipped with the run-on bevel 111 protrude slightly laterally compared to the stiffening ribs 128.

[0053] Compared to the prior art, the battery pack according to the invention enables a significantly greater level of automation while simultaneously reducing the number of parts. Furthermore, the battery pack according to the invention features a compact design, which, thanks to its effective cooling function, also enables use with higher-performance battery cells. The present invention therefore represents a very special contribution to the relevant field of the prior art.

[0054] REFERENCE MARKS LIST

[0055] 100 battery pack

[0056] 101 first cell holder

[0057] 102 second cell holder

[0058] 103 Sheath element

[0059] 104 first end area

[0060] 105 second end area

[0061] 106 first connecting devices

[0062] 107 second connecting means

[0063] 108 first recording room

[0064] 109 second recording room

[0065] 110 snapper

[0066] 111 Run-up slope

[0067] 112 hollow cylinders

[0068] 113 Recess

[0069] 114 first cell connector

[0070] 115 second cell connector

[0071] 116 first press-fit pin

[0072] 117 second press-fit pin

[0073] 118 distance

[0074] 119 first tongue

[0075] 120 second tongue

[0076] 121 Area of ​​the first cell holder

[0077] 122 first connection tab

[0078] 123 second connection tab

[0079] 124 slot

[0080] 125 bore

[0081] 126 first holding projection

[0082] 127 second holding projection

[0083] 128 Stiffening rib

[0084] 300 battery pack control device

[0085] 301 Printed circuit board 302 First side of the printed circuit board

[0086] 302 second side of the circuit board

[0087] 303 passage opening

[0088] 304 Hole 305 Clamp

[0089] 400 first housing shell

[0090] 401 second housing shell

[0091] 402 bulge

Claims

PA TE N TA NSP RÜ CHE 1. A battery pack (100) comprising a plurality of battery cells, a battery pack control device (300), which preferably comprises a circuit board (301), at least one cell connector (114, 115) for electrically connecting the battery cells, a first and a second cell holder (101, 102), wherein the first and second cell holders (101, 102) each form a first and a second receiving space (108, 109) for a first and an opposite second end region (201, 202) of each battery cell, a casing element (103) which surrounds the battery cells completely over their outer circumference, preferably without a gap, wherein the casing element (103) has a first end region (104) and, viewed in the longitudinal direction of the battery cells, bridges a distance (118) between the first and second cell holders (101, 102), and first connecting means (106) in the region of the first cell holder (101) and the first end region (104) of the casing element (103).

2. Battery pack (100) according to claim 1, characterized in that the casing element (103) has a second end region (104, 105) and second connecting means (107) are provided in the region of the second cell holder (102) and the second end region (105) of the casing element (103).

3. Battery pack (100) according to the preceding claims, characterized in that the first and / or second connecting means (106, 107) are designed such that a connection by means of the first or second connecting means (106, 107) is automatically activated by a longitudinal joining of the first or second cell holder (101, 102) and the casing element (103) to one another.

4. Battery pack (100) according to the preceding claims, characterized in that the first and / or second connecting means (106, 107) are snap-on connecting means.

5. Battery pack (100) according to the preceding claims, characterized in that the first and / or second connecting means (106, 107) comprise a preferably annular, movable snap-in element (109) and a run-on slope (110) for the snap-in element (109).

6. Battery pack (100) according to the preceding claims, characterized in that the first and / or second connecting means (106, 107) are arranged in the respective side region of the first and second cell holder (101, 102) and in the side region of the casing element (103), preferably on both sides and / or opposite one another.

7. Battery pack (100) according to the preceding claims, characterized in that the casing element (103) is constructed from individual hollow cylinders (112) arranged in a row, wherein two adjacent hollow cylinders (112) each form a recess (113) in the lateral outer region.

8. Battery pack (100) according to claim 7, characterized in that the first and / or second connecting means (106, 107) are each located completely or partially in a lateral recess (113) formed by two adjacent hollow cylinders (112).

9. Battery pack (100) according to the preceding claims, characterized in that the first and / or second cell holder (101, 102) is or are an injection-molded part at least partially enclosing the cell connector (114, 115).

10. Battery pack (100) according to the preceding claims, characterized in that the cell connector (113, 114) has at least one press-fit pin (116, 117) and the cell connector (114, 115) forms a press-fit connection with a printed circuit board (301) of a battery pack control device (300) via its at least one press-fit pin (116, 117).

11. Battery pack (100) according to claims 7 to 10, characterized in that a part (121) of the first and / or second cell holder (101, 102) and / or a part of the cell connector (114, 115) is accommodated in the lateral recess (113) formed by two adjacent hollow cylinders (112).

12. Battery pack (100) according to the preceding claims, characterized in that the casing element (103) comprises a cooling function.

13. Battery pack (100) according to the preceding claims, characterized in that the casing element (103) consists of a plastic material and a plastic compound material comprising filler material, wherein the thermal conductivity of the filler material is higher than that of the plastic material.

14. Battery pack (100) according to claim 13, characterized in that the plastic compound material has a thermal conductivity A of at least 0.5 W / mK, preferably of at least 1.0 W / mK, particularly preferably of at least 2.0 W / mK.

15. Battery pack (100) according to the preceding claims, characterized in that a first cell connector (114) is arranged on the first end region (201) and a second cell connector (115) is arranged on the opposite second end region (202) of the battery cell, the first cell connector (114) is fed to the circuit board (301) from its first side (302) and the second cell connector (115) is fed to the circuit board (301) from its second side (302) opposite the first side (301) and are electrically contacted with the circuit board (301), preferably via press-fit pins (116, 117).

16. Battery pack (100) according to the preceding claims, characterized in that the first and second cell holders (101, 102) and / or the first and second cell connectors (114, 115) have an identical shape.

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